Bump websockets from 9.1 to 12.0

Bumps [websockets](https://github.com/python-websockets/websockets) from 9.1 to 12.0.
- [Release notes](https://github.com/python-websockets/websockets/releases)
- [Commits](python-websockets/websockets@9.1...12.0)

---
updated-dependencies:
- dependency-name: websockets
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,4 +1,4 @@
 aiohttp==3.7.4
-websockets==9.1
+websockets==12.0
 PyJWT==2.4.0
 pytz==2019.3