Bump idna from 3.2 to 3.7 in /docs

Bumps [idna](https://github.com/kjd/idna) from 3.2 to 3.7.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](kjd/idna@v3.2...v3.7)

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

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

docs/rtd-requirements.txt

@@ -5,7 +5,7 @@ certifi==2023.7.22
 charset-normalizer==2.0.6
 decorator==5.1.0
 docutils==0.17.1
-idna==3.2
+idna==3.7
 imagesize==1.2.0
 ipython==7.31.1
 jedi==0.18.0