Bump alabaster from 0.7.12 to 0.7.13 (#544)

Bumps [alabaster](https://github.com/bitprophet/alabaster) from 0.7.12 to 0.7.13.
- [Release notes](https://github.com/bitprophet/alabaster/releases)
- [Changelog](https://github.com/bitprophet/alabaster/blob/main/docs/changelog.rst)
- [Commits](sphinx-doc/alabaster@0.7.12...0.7.13)

---
updated-dependencies:
- dependency-name: alabaster
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

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

docs-requirements.txt

@@ -4,7 +4,7 @@
 #
 #    pip-compile docs-requirements.in
 #
-alabaster==0.7.12
+alabaster==0.7.13
     # via sphinx
 babel==2.11.0
     # via sphinx