Bump mkdocs from 1.4.2 to 1.5.3 (#818)

Bumps [mkdocs](https://github.com/mkdocs/mkdocs) from 1.4.2 to 1.5.3.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](mkdocs/mkdocs@1.4.2...1.5.3)

---
updated-dependencies:
- dependency-name: mkdocs
  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: Kar Petrosyan <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -4,7 +4,7 @@
 trio==0.21.0
 
 # Docs
-mkdocs==1.4.2
+mkdocs==1.5.3
 mkdocs-autorefs==0.5.0
 mkdocs-material==9.1.15
 mkdocs-material-extensions==1.1.1