Bump idna from 2.9 to 3.7

Bumps [idna](https://github.com/kjd/idna) from 2.9 to 3.7.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.rst)
- [Commits](kjd/idna@v2.9...v3.7)

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

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

Author: dependabot[bot]

requirements.txt

@@ -8,7 +8,7 @@ gast==0.2.2
 google-pasta==0.2.0
 grpcio==1.29.0
 h5py==2.10.0
-idna==2.9
+idna==3.7
 imageio==2.8.0
 importlib-metadata==1.6.0
 joblib==0.14.1