Bump sphinx-gallery from 0.17.1 to 0.18.0 (#722)

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

requirements/requirements_docs.txt

@@ -9,7 +9,7 @@ sphinxcontrib-websupport==2.0.0
 pytest-sphinx==0.6.3
 sphinx-notfound-page==1.0.4
 sphinx-copybutton==0.5.0
-sphinx-gallery==0.17.1
+sphinx-gallery==0.18.0
 ansys_sphinx_theme==1.0.11
 sphinx-autodoc-typehints==2.4.4; python_version == '3.8'
 sphinx-autodoc-typehints==2.4.4; python_version >= '3.9'