Update alabaster requirement from <0.8 to <1.1

Updates the requirements on [alabaster](https://github.com/sphinx-doc/alabaster) to permit the latest version.
- [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@0.1.0...1.0.0)

---
updated-dependencies:
- dependency-name: alabaster
  dependency-type: direct:production
...

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

docs/requirements.txt

@@ -1,4 +1,4 @@
-alabaster<0.8
+alabaster<1.1
 jinja2<3.2
 markupsafe<4
 readme-renderer<45