- update to 2.2.0:
* Drop support for Python 3.7. :pr:`372`
* Use modern packaging metadata with pyproject.toml instead of
setup.cfg. :pr:`326`
* Use flit_core instead of setuptools as build backend.
* Deprecate the __version__ attribute. Use feature detection,
or importlib.metadata.version("itsdangerous"), instead.
:issue:`371`
* Serializer and the return type of dumps is generic for type
checking. By default it is Serializer[str] and dumps returns
a str. If a different serializer argument is given, it will
try to infer the return type of its dumps method.
:issue:`347`
* The default hashlib.sha1 may not be available in FIPS builds.
Don't access it at import time so the developer has time to
change the default. :issue:`375`