Bump actions/setup-python from 2.3.2 to 4.2.0 (#196)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 2.3.2 to 4.2.0.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@7f80679...b55428b)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/docs.yml

@@ -28,7 +28,7 @@ jobs:
             pypi.org:443
 
       - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - uses: actions/setup-python@7f80679172b057fc5e90d70d197929d454754a5a
+      - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
         with:
           python-version: 3.x
       - run: pip install mkdocs-material mkdocs-awesome-pages-plugin