Bump pydata-sphinx-theme from 0.15.3 to 0.15.4 (#817)

Bumps [pydata-sphinx-theme](https://github.com/pydata/pydata-sphinx-theme) from 0.15.3 to 0.15.4.
- [Release notes](https://github.com/pydata/pydata-sphinx-theme/releases)
- [Changelog](https://github.com/pydata/pydata-sphinx-theme/blob/main/RELEASE.md)
- [Commits](pydata/pydata-sphinx-theme@v0.15.3...v0.15.4)

---
updated-dependencies:
- dependency-name: pydata-sphinx-theme
  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>

Author: dependabot[bot]

requirements.txt

@@ -26,7 +26,7 @@ nodeenv==1.9.1
 packaging==24.1
 platformdirs==4.2.2
 pre-commit==3.8.0
-pydata-sphinx-theme==0.15.3
+pydata-sphinx-theme==0.15.4
 pyenchant==3.2.2
 Pygments==2.18.0
 python-debian==0.1.49