build: bump idna from 3.4 to 3.7 in /.github/workflows

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: indirect
...

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

.github/workflows/mkdocs-requirements.txt

@@ -4,7 +4,7 @@ charset-normalizer==2.1.1
 click==8.1.3
 colorama==0.4.6
 ghp-import==2.1.0
-idna==3.4
+idna==3.7
 importlib-metadata==6.8.0
 importlib-resources==6.1.0
 jinja2==3.1.3