Bump packaging from 20.8 to 20.9

Bumps [packaging](https://github.com/pypa/packaging) from 20.8 to 20.9.
- [Release notes](https://github.com/pypa/packaging/releases)
- [Changelog](https://github.com/pypa/packaging/blob/main/CHANGELOG.rst)
- [Commits](pypa/packaging@20.8...20.9)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

docs-requirements.txt

@@ -22,7 +22,7 @@ jinja2==2.11.2
     # via sphinx
 markupsafe==1.1.1
     # via jinja2
-packaging==20.8
+packaging==20.9
     # via sphinx
 pygments==2.7.4
     # via sphinx

test-requirements.txt

@@ -36,7 +36,7 @@ lxml==4.6.2
     # via -r test-requirements.in
 markupsafe==1.1.1
     # via jinja2
-packaging==20.8
+packaging==20.9
     # via
     #   pytest
     #   sphinx