py-setuptools: updated to 51.3.3

v51.3.3

Misc
* Fix AttributeError in Description validation.

v51.3.2

Misc
* Validation of Description field now is more lenient, emitting a warning and mangling the value to be valid (replacing newlines with spaces).

v51.3.1

Misc
* Reverted tag deduplication handling.

v51.3.0

Changes
* Newlines in metadata description/Summary now trigger a ValueError.
* Define create_module() and exec_module() methods in VendorImporter to get rid of ImportWarning -- by :user:`hroncok`
* pkg_resources behavior for zipimport now matches the regular behavior, and finds .egg-info (previoulsy would only find .dist-info) -- by :user:`thatch`
* Fixed an issue where version tags may be added multiple times

v51.2.0

Changes
* Use importlib.import_module() rather than the deprectated loader.load_module() in pkg_resources namespace delaration -- by :user:`encukou`

Documentation changes
* Fix typo in the document page about entry point. -- by :user:`jtr109`

Misc
* Avoid hitting network during test_easy_install.

v51.1.2

Misc
* Disable inclusion of package data as it causes 'tests' to be included as data.

v51.1.1

Misc
* Avoid hitting network during test_virtualenv.test_test_command.

v51.1.0

Changes
* Project adopts jaraco/skeleton for shared package maintenance.

Misc
* Restore inclusion of rst files in sdist.
* Setuptools has replaced the master branch with the main branch.
* Fixed failing test when pip 20.3+ is present. -- by :user:`yan12125`
* Fix tests with pytest 6.2 -- by :user:`yan12125`

v51.0.0

Breaking Changes
* Require Python 3.6 or later.

Documentation changes
* Fixed inconsistent RST title nesting levels caused
* Fixed a typo in Sphinx docs that made docs dev section disappear

Misc
* Removed the tests that guarantee that the vendored dependencies can be built by distutils.

(adam)