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] <support@github.com>

requirements.txt

@@ -3,7 +3,7 @@ charset-normalizer==3.3.2
 cloudscale-sdk==0.7.0
 cs==3.2.0
 hcloud==1.35.0
-idna==3.6
+idna==3.7
 jsonpickle==3.0.2
 proxmoxer==1.3.1
 python-dateutil==2.8.2