Chore(deps): Bump idna from 3.4 to 3.7 in /docs (#827)

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] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -16,7 +16,7 @@ docutils==0.18.1
     # via
     #   sphinx
     #   sphinx-rtd-theme
-idna==3.4
+idna==3.7
     # via requests
 imagesize==1.4.1
     # via sphinx