Bump mkdocs-material-extensions from 1.0.1 to 1.0.3

Bumps [mkdocs-material-extensions](https://github.com/facelessuser/mkdocs-material-extensions) from 1.0.1 to 1.0.3.
- [Release notes](https://github.com/facelessuser/mkdocs-material-extensions/releases)
- [Changelog](https://github.com/facelessuser/mkdocs-material-extensions/blob/master/changelog.md)
- [Commits](https://github.com/facelessuser/mkdocs-material-extensions/compare/1.0.1...1.0.3)

---
updated-dependencies:
- dependency-name: mkdocs-material-extensions
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

docs/requirements.txt

@@ -3,7 +3,7 @@ git+https://github.com/g-provost/lightgallery-markdown@v0.5#egg=lightgallery
 markdown==3.3.4
 mkdocs-awesome-pages-plugin==2.5.0
 mkdocs-git-revision-date-localized-plugin==0.9.2
-mkdocs-material-extensions==1.0.1
+mkdocs-material-extensions==1.0.3
 mkdocs-material==7.2.6
 mkdocs-minify-plugin==0.4.0
 mkdocs-redirects==1.0.3