⬆️ Bump idna from 3.4 to 3.7 in /docs/mkdocs

Bumps [idna](https://github.com/kjd/idna) from 3.4 to 3.7.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](kjd/idna@v3.4...v3.7)

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

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

docs/mkdocs/requirements.txt

@@ -9,7 +9,7 @@ gitdb==4.0.11
 GitPython==3.1.40
 htmlmin==0.1.12
 httplib2==0.22.0
-idna==3.4
+idna==3.7
 importlib-metadata==6.8.0
 Jinja2==3.1.2
 joblib==1.3.2