build(deps): bump sphinx-gallery from 0.17.1 to 0.18.0 in /requirements

Bumps [sphinx-gallery](https://github.com/sphinx-gallery/sphinx-gallery) from 0.17.1 to 0.18.0.
- [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@v0.17.1...v0.18.0)

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

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

requirements/_docs.txt

@@ -10,7 +10,7 @@ sphinx-paramlinks ==0.6.0
 sphinx-togglebutton ==0.3.2
 sphinx-copybutton ==0.5.2
 sphinx-autobuild ==2024.10.3
-sphinx-gallery ==0.17.1
+sphinx-gallery ==0.18.0
 
 lightning >=1.8.0, <2.5.0
 lightning-utilities ==0.11.7