Bump alabaster from 0.7.15 to 0.7.16 (#680)

Bumps [alabaster](https://github.com/sphinx-doc/alabaster) from 0.7.15 to 0.7.16.
- [Release notes](https://github.com/sphinx-doc/alabaster/releases)
- [Changelog](https://github.com/sphinx-doc/alabaster/blob/master/docs/changelog.rst)
- [Commits](sphinx-doc/alabaster@0.7.15...0.7.16)

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

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

requirements.txt

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
 accessible-pygments==0.0.4
-alabaster==0.7.15
+alabaster==0.7.16
 Babel==2.14.0
 beautifulsoup4==4.12.3
 binaryornot==0.4.4