py-flask: updated to 2.2.1

Version 2.2.1
-------------
-  Setting or accessing ``json_encoder`` or ``json_decoder`` raises a
    deprecation warning.

Version 2.2.0
-------------
-  Remove previously deprecated code.

    -  Old names for some ``send_file`` parameters have been removed.
        ``download_name`` replaces ``attachment_filename``, ``max_age``
        replaces ``cache_timeout``, and ``etag`` replaces ``add_etags``.
        Additionally, ``path`` replaces ``filename`` in
        ``send_from_directory``.
    -  The ``RequestContext.g`` property returning ``AppContext.g`` is
        removed.

-  Update Werkzeug dependency to >= 2.2.
-  The app and request contexts are managed using Python context vars
    directly rather than Werkzeug's ``LocalStack``. This should result
    in better performance and memory use.

    -  Extension maintainers, be aware that ``_app_ctx_stack.top``
        and ``_request_ctx_stack.top`` are deprecated. Store data on
        ``g`` instead using a unique prefix, like
        ``g._extension_name_attr``.

-  The ``FLASK_ENV`` environment variable and ``app.env`` attribute are
    deprecated, removing the distinction between development and debug
    mode. Debug mode should be controlled directly using the ``--debug``
    option or ``app.run(debug=True)``.
-  Some attributes that proxied config keys on ``app`` are deprecated:
    ``session_cookie_name``, ``send_file_max_age_default``,
    ``use_x_sendfile``, ``propagate_exceptions``, and
    ``templates_auto_reload``. Use the relevant config keys instead.

-  Add new customization points to the ``Flask`` app object for many
    previously global behaviors.

    -  ``flask.url_for`` will call ``app.url_for``.
    -  ``flask.abort`` will call ``app.aborter``.
        ``Flask.aborter_class`` and ``Flask.make_aborter`` can be used
        to customize this aborter.
    -  ``flask.redirect`` will call ``app.redirect``.
    -  ``flask.json`` is an instance of ``JSONProvider``. A different
        provider can be set to use a different JSON library.
        ``flask.jsonify`` will call ``app.json.response``, other
        functions in ``flask.json`` will call corresponding functions in
        ``app.json``.

-  JSON configuration is moved to attributes on the default
    ``app.json`` provider. ``JSON_AS_ASCII``, ``JSON_SORT_KEYS``,
    ``JSONIFY_MIMETYPE``, and ``JSONIFY_PRETTYPRINT_REGULAR`` are
    deprecated.
-  Setting custom ``json_encoder`` and ``json_decoder`` classes on the
    app or a blueprint, and the corresponding ``json.JSONEncoder`` and
    ``JSONDecoder`` classes, are deprecated. JSON behavior can now be
    overridden using the ``app.json`` provider interface.
-  ``json.htmlsafe_dumps`` and ``json.htmlsafe_dump`` are deprecated,
    the function is built-in to Jinja now.
-  Refactor ``register_error_handler`` to consolidate error checking.
    Rewrite some error messages to be more consistent.
-  Use Blueprint decorators and functions intended for setup after
    registering the blueprint will show a warning. In the next version,
    this will become an error just like the application setup methods.

-  ``before_first_request`` is deprecated. Run setup code when creating
    the application instead.
-  Added the ``View.init_every_request`` class attribute. If a view
    subclass sets this to ``False``, the view will not create a new
    instance on every request.
-  A ``flask.cli.FlaskGroup`` Click group can be nested as a
    sub-command in a custom CLI.
-  Add ``--app`` and ``--debug`` options to the ``flask`` CLI, instead
    of requiring that they are set through environment variables.

-  Add ``--env-file`` option to the ``flask`` CLI. This allows
    specifying a dotenv file to load in addition to ``.env`` and
    ``.flaskenv``.
-  It is no longer required to decorate custom CLI commands on
    ``app.cli`` or ``blueprint.cli`` with ``@with_appcontext``, an app
    context will already be active at that point.
-  ``SessionInterface.get_expiration_time`` uses a timezone-aware
    value.
-  View functions can return generators directly instead of wrapping
    them in a ``Response``.
-  Add ``stream_template`` and ``stream_template_string`` functions to
    render a template as a stream of pieces.
-  A new implementation of context preservation during debugging and
    testing.

    -  ``request``, ``g``, and other context-locals point to the
        correct data when running code in the interactive debugger
        console.
    -  Teardown functions are always run at the end of the request,
        even if the context is preserved. They are also run after the
        preserved context is popped.
    -  ``stream_with_context`` preserves context separately from a
        ``with client`` block. It will be cleaned up when
        ``response.get_data()`` or ``response.close()`` is called.

-  Allow returning a list from a view function, to convert it to a
    JSON response like a dict is.
-  When type checking, allow ``TypedDict`` to be returned from view
    functions.
-  Remove the ``--eager-loading/--lazy-loading`` options from the
    ``flask run`` command. The app is always eager loaded the first
    time, then lazily loaded in the reloader. The reloader always prints
    errors immediately but continues serving. Remove the internal
    ``DispatchingApp`` middleware used by the previous implementation.

(adam)