Bump idna from 3.6 to 3.7

Bumps [idna](https://github.com/kjd/idna) from 3.6 to 3.7.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](kjd/idna@v3.6...v3.7)

---
updated-dependencies:
- dependency-name: idna
  dependency-type: indirect
...

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

Author: dependabot[bot]

requirements.txt

@@ -16,7 +16,7 @@ docutils==0.20.1
     # via
     #   sphinx
     #   sphinx-rtd-theme
-idna==3.6
+idna==3.7
     # via requests
 imagesize==1.4.1
     # via sphinx