CI: (deps): Bump pydata-sphinx-theme from 0.8.1 to 0.12.0 in /ci

Bumps [pydata-sphinx-theme](https://github.com/pydata/pydata-sphinx-theme) from 0.8.1 to 0.12.0.
- [Release notes](https://github.com/pydata/pydata-sphinx-theme/releases)
- [Commits](pydata/pydata-sphinx-theme@v0.8.1...v0.12.0)

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

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

Author: dependabot[bot]

ci/doc_requirements.txt

@@ -1,5 +1,5 @@
 sphinx==4.5.0
-pydata-sphinx-theme==0.8.1
+pydata-sphinx-theme==0.12.0
 sphinx-gallery==0.10.1
 myst-parser==0.18.0
 netCDF4==1.5.8