Bump sphinx-gallery from 0.18.0 to 0.19.0 in /requirements (#2079)

Bumps [sphinx-gallery](https://github.com/sphinx-gallery/sphinx-gallery) from 0.18.0 to 0.19.0.
- [Release notes](https://github.com/sphinx-gallery/sphinx-gallery/releases)
- [Changelog](https://github.com/sphinx-gallery/sphinx-gallery/blob/master/.github_changelog_generator)
- [Commits](sphinx-gallery/sphinx-gallery@v0.18.0...v0.19.0)

---
updated-dependencies:
- dependency-name: sphinx-gallery
  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>
Co-authored-by: Muhammed Adedigba <[email protected]>

Author: dependabot[bot]

requirements/requirements_docs.txt

@@ -9,7 +9,7 @@ pytest-sphinx==0.6.3
 pyvista==0.44.2
 sphinx==7.4.7
 sphinx-copybutton==0.5.2
-sphinx-gallery==0.18.0
+sphinx-gallery==0.19.0
 sphinx-notfound-page==1.1.0
 sphinx-reredirects==0.1.3
 sphinx_design==0.6.1