Bump mkdocs from 1.0.4 to 1.2.3

Bumps [mkdocs](https://github.com/mkdocs/mkdocs) from 1.0.4 to 1.2.3.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](mkdocs/mkdocs@1.0.4...1.2.3)

---
updated-dependencies:
- dependency-name: mkdocs
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -5,7 +5,7 @@ Jinja2==2.11.3
 livereload==2.6.1
 Markdown==3.2.1
 MarkupSafe==1.1.1
-mkdocs==1.0.4
+mkdocs==1.2.3
 mkdocs-material==4.6.3
 Pygments==2.7.4
 pymdown-extensions==6.3