Bump websockets from 7.0 to 9.1

Bumps [websockets](https://github.com/aaugustin/websockets) from 7.0 to 9.1.
- [Release notes](https://github.com/aaugustin/websockets/releases)
- [Changelog](https://github.com/aaugustin/websockets/blob/9.1/docs/changelog.rst)
- [Commits](https://github.com/aaugustin/websockets/compare/7.0...9.1)

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

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

requirements.txt

@@ -27,7 +27,7 @@ soupsieve==1.6.2
 tqdm==4.28.1
 urllib3==1.24.2
 w3lib==1.19.0
-websockets==7.0
+websockets==9.1
 Werkzeug==0.15.5
 DingtalkChatbot==1.3.0
 lightpush==0.1.3