Bump sphinx from 5.0.2 to 5.1.1 (#360)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 5.0.2 to 5.1.1.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/5.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v5.0.2...v5.1.1)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

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

doc/requirements.txt

@@ -1,7 +1,7 @@
 click==8.1.3
 entrypoints==0.4
 Pillow==9.2.0
-Sphinx==5.0.2
+Sphinx==5.1.1
 sphinx-rtd-theme==1.0.0
 ipython==8.4.0
 netCDF4==1.6.0