build: bump mkdocs-material from 9.1.18 to 9.1.19 in /.github/workflows

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.1.18 to 9.1.19.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.1.18...9.1.19)

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

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

.github/workflows/mkdocs-requirements.in

@@ -1,3 +1,3 @@
 mike==1.1.2
-mkdocs-material==9.1.18
+mkdocs-material==9.1.19
 mkdocs-material-extensions==1.1.1

.github/workflows/mkdocs-requirements.txt

@@ -10,7 +10,7 @@ markupsafe==2.1.1
 mergedeep==1.3.4
 mike==1.1.2
 mkdocs==1.4.2
-mkdocs-material==9.1.18
+mkdocs-material==9.1.19
 mkdocs-material-extensions==1.1.1
 packaging==22.0
 pygments==2.14.0