Log Message:
py-cssutils: updated to 2.9.0

v2.9.0
Features
- Made URL fetcher lenient to missing metadata.

v2.8.0
Features
- Require Python 3.8 or later.

Bugfixes
- Made some unreachable tests reachable.

v2.7.1
Refactored to restore docs builds without warning-errors.

v2.7.0
Updated deprecated usage of ``cgi`` module.
Updated deprecated setup/teardown from ``nose`` in tests.
Other miscellaneous cleanup and packaging updates.

v2.6.0
Added support for custom CSS variables with ``--`` prefix.

v2.5.1
Some refactoring.

v2.5.0
Substantial code refresh. Ported tests to native pytest.
Enrolled project with Tidelift.