py-tox: updated to 3.20.1

v3.20.1 (2020-10-09)
--------------------

Bugfixes
- Relax importlib requirement to allow version<3 - by :user:`usamasadiq`

v3.20.0 (2020-09-01)
--------------------

Bugfixes
- Allow hyphens and empty factors in generative section name. - by :user:`tyagdit`
- Support for PEP517 in-tree build backend-path key in ``get-build-requires``. - by :user:`nizox`
- Allow escaping curly braces in setenv. - by :user:`mkenigs`

Features
- Support for comments within ``setenv`` and environment files via the ``files|`` prefix. - by :user:`gaborbernat`

v3.19.0 (2020-08-06)
--------------------

Bugfixes
- skip ``setup.cfg`` if it has no ``tox:tox`` namespace - by :user:`hroncok`

Features
- Implement support for building projects
  having :pep:`517#in-tree-build-backends` ``backend-path`` setting -
- Don't require a tox config file for ``tox --devenv`` - by :user:`hroncok`

Documentation
- Fixed grammar in top-level documentation - by :user:`tfurf`

v3.18.1 (2020-07-28)
--------------------

Bugfixes
- Fix ``TypeError`` when using isolated_build with backends that are not submodules (e.g. ``maturin``)

v3.18.0 (2020-07-23)
--------------------

Deprecations (removal in next major release)
- Add allowlist_externals alias to whitelist_externals (whitelist_externals is now deprecated). - by :user:`dajose`

v3.17.1 (2020-07-15)
--------------------

Bugfixes
- Fix tests when the ``HOSTNAME`` environment variable is set, but empty string - by :user:`hroncok`

v3.17.0 (2020-07-14)
--------------------

Features
- The long arguments ``--verbose`` and ``--quiet`` (rather than only their short forms, ``-v`` and ``-q``) are now accepted.
- The ``ResultLog`` now prefers ``HOSTNAME`` environment variable value (if set) over the full qualified domain name of localhost.
  This makes it possible to disable an undesired DNS lookup,
  which happened on all ``tox`` invocations, including trivial ones - by :user:`hroncok`

Documentation
- Update packaging information for Flit.

v3.16.1 (2020-06-29)
--------------------

Bugfixes
- Fixed the support for using ``{temp_dir}`` in ``tox.ini`` - by :user:`webknjaz`

v3.16.0 (2020-06-26)
--------------------

Features
- Allow skipping the package and installation step when passing the ``--skip-pkg-install``. This should be used in pair with the ``--notest``, so you can separate environment setup and test run:

   .. code-block:: console

      tox -e py --notest
      tox -e py --skip-pkg-install

Miscellaneous
- Improve config parsing performance by precompiling commonly used regular expressions - by :user:`brettlangdon`

v3.15.2 (2020-06-06)
--------------------

Bugfixes
- Add an option to allow a process to suicide before sending the SIGTERM. - by :user:`jhesketh`
- PyPy 7.3.1 on Windows uses the ``Script`` folder instead of ``bin``. - by :user:`gaborbernat`

Miscellaneous
- Allow to run the tests with pip 19.3.1 once again while preserving the ability to use pip 20.1 - by :user:`hroncok`

v3.15.1 (2020-05-20)
--------------------

Bugfixes
- ``tox --showconfig`` no longer tries to interpolate '%' signs.

v3.15.0 (2020-05-02)
--------------------

Bugfixes
- Respect attempts to change ``PATH`` via ``setenv`` - by :user:`aklajnert`.
- Fix parsing of architecture in python interpreter name. - by :user:`bruchar1`
- Prevent exception when command is empty. - by :user:`bruchar1`
- Fix irrelevant Error message for invalid argument when running outside a directory with tox support files by :user:`nkpro2000sr`.

Features
- Allow parallel mode without arguments. - by :user:`ssbarnea`
- Allow generative section name expansion. - by :user:`bruchar1`
- default to passing the env var PIP_EXTRA_INDEX_URL by :user:`georgealton`.

Documentation
- Improve documentation about config by adding tox environment description at start - by :user:`stephenfin`.

v3.14.6 (2020-03-25)
--------------------

Bugfixes
- Exclude virtualenv dependency versions with known
  regressions (20.0.[0-7]) - by :user:`webknjaz`.
- Fix ``tox -h`` and ``tox --hi`` shows an error when run outside a directory with tox support files by :user:`nkpro2000sr`.
- Fix ValueError on ``tox -l`` for a ``tox.ini`` file that does not contain an
  ``envlist`` definition. - by :user:`jquast`.

v3.14.5 (2020-02-16)
--------------------

Features
- Add ``--discover`` (fallback to ``TOX_DISCOVER`` environment variable via path separator) to inject python executables
  to try as first step of a discovery - note the executable still needs to match the environment by :user:`gaborbernat`.

v3.14.4 (2020-02-13)
--------------------

Bugfixes
- Bump minimal six version needed to avoid using one incompatible with newer
  virtualenv. - by :user:`ssbarnea`
- Avoid pypy test failure due to undefined printout var. - by :user:`ssbarnea`

Features
- Add ``interrupt_timeout`` and ``terminate_timeout`` that configure delay between SIGINT, SIGTERM and SIGKILL when tox is interrupted. - by :user:`sileht`
- Add ``HTTP_PROXY``, ``HTTPS_PROXY`` and ``NO_PROXY`` to default passenv. - by :user:`pfmoore`

v3.14.3 (2019-12-27)
--------------------

Bugfixes
- Relax importlib requirement to allow either version 0 or 1 - by :user:`chyzzqo2`

Miscellaneous
- Clarify legacy setup.py error message: python projects should commit to a strong consistency of message regarding packaging. We no-longer tell people to add a setup.py to their already configured pep-517 project, otherwise it could imply that pyproject.toml isn't as well supported and recommended as it truly is - by :user:`graingert`

v3.14.2 (2019-12-02)
--------------------

Bugfixes
- Fix fallback to global configuration when running in Jenkins. - by :user:`daneah`
- Fix colouring on windows: colorama is a dep. - by :user:`1138-4EB`

Miscellaneous
- improve performance with internal lookup of Python version information - by :user:`blueyed`
- Use latest version of importlib_metadata package - by :user:`kammala`
- Mark poetry related tests as xfail since its dependency pyrsistent won't install in ci due to missing wheels/build deps. - by :user:`RonnyPfannschmidt`

v3.14.1 (2019-11-13)
--------------------

Bugfixes
- fix reporting of exiting due to (real) signals - by :user:`blueyed`
- Bump minimal virtualenv to 16.0.0 to improve own transitive
  deps handling in some ancient envs. — by :user:`webknjaz`
- Adds ``CURL_CA_BUNDLE``, ``REQUESTS_CA_BUNDLE``, ``SSL_CERT_FILE`` to the default passenv values. - by :user:`ssbarnea`
- Fix nested tox execution in the parallel mode by separating the environment
  variable that let's tox know it is invoked in the parallel mode
  (``_TOX_PARALLEL_ENV``) from the variable that informs the tests that tox is
  running in parallel mode (``TOX_PARALLEL_ENV``).
- Fix provisioning from a pyvenv interpreter. — by :user:`kentzo`

Deprecations (removal in next major release)
- Python ``3.4`` is no longer supported. — by :user:`gaborbernat`

v3.14.0 (2019-09-03)
--------------------

Bugfixes
- Fix ``PythonSpec`` detection of ``python3.10`` - by :user:`asottile`
- Fix regression failing to detect future and past ``py##`` factors  - by :user:`asottile`
- Fix ``current_tox_py`` for ``pypy`` / ``pypy3`` - by :user:`asottile`
- Honor environment markers in ``requires`` list - by :user:`asottile`
- improve recreate check by allowing directories containing ``.tox-config1`` (the marker file created by tox) - by :user:`asottile`
- Recognize correctly interpreters that have suffixes (like python3.7-dbg).

Features
- Add support for minor versions with multiple digits ``tox -e py310`` works for ``python3.10`` - by :user:`asottile`
- Remove dependence on ``md5`` hashing algorithm - by :user:`asottile`

Documentation
- clarify behaviour if recreate is set to false - by :user:`PJCampi`

Miscellaneous
- Fix relative URLs to files in the repo in ``.github/PULL_REQUEST_TEMPLATE.md`` — by :user:`webknjaz`
- Replace ``importlib_metadata`` backport with ``importlib.metadata``
  from the standard library on Python ``3.8+`` - by :user:`hroncok`
- Render the change fragment help on the ``docs/changelog/`` directory view on GitHub


(adam)