chore(deps): bump mkdocs-material from 9.5.20 to 9.5.21 in /docs

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.5.20 to 9.5.21.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.5.20...9.5.21)

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

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

Author: dependabot[bot]

docs/requirements.in

@@ -1,4 +1,4 @@
 mike==1.1.2
-mkdocs-material==9.5.20
+mkdocs-material==9.5.21
 mkdocs-git-revision-date-plugin==0.3.2
 mkdocs-exclude==1.0.2

docs/requirements.txt

@@ -235,9 +235,9 @@ mkdocs-get-deps==0.2.0 \
 mkdocs-git-revision-date-plugin==0.3.2 \
     --hash=sha256:2e67956cb01823dd2418e2833f3623dee8604cdf223bddd005fe36226a56f6ef
     # via -r requirements.in
-mkdocs-material==9.5.20 \
-    --hash=sha256:986eef0250d22f70fb06ce0f4eac64cc92bd797a589ec3892ce31fad976fe3da \
-    --hash=sha256:ad0094a7597bcb5d0cc3e8e543a10927c2581f7f647b9bb4861600f583180f9b
+mkdocs-material==9.5.21 \
+    --hash=sha256:049f82770f40559d3c2aa2259c562ea7257dbb4aaa9624323b5ef27b2d95a450 \
+    --hash=sha256:210e1f179682cd4be17d5c641b2f4559574b9dea2f589c3f0e7c17c5bd1959bc
     # via -r requirements.in
 mkdocs-material-extensions==1.3.1 \
     --hash=sha256:10c9511cea88f568257f960358a467d12b970e1f7b2c0e5fb2bb48cab1928443 \