Bump packaging from 20.9 to 21.0 (#70)

Bumps [packaging](https://github.com/pypa/packaging) from 20.9 to 21.0.
- [Release notes](https://github.com/pypa/packaging/releases)
- [Changelog](https://github.com/pypa/packaging/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/pypa/packaging/compare/20.9...21.0)

---
updated-dependencies:
- dependency-name: packaging
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements-dev.txt

@@ -11,7 +11,7 @@ idna==2.10
 importlib-metadata==4.5.0
 jeepney==0.6.0
 keyring==23.0.1
-packaging==20.9
+packaging==21.0
 pkginfo==1.7.0
 pycparser==2.20
 Pygments==2.9.0