Update websockets requirement from ==11.* to ==12.* in /server

Updates the requirements on [websockets](https://github.com/python-websockets/websockets) to permit the latest version.
- [Release notes](https://github.com/python-websockets/websockets/releases)
- [Commits](python-websockets/websockets@11.0...12.0)

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

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

server/requirements.txt

@@ -32,7 +32,7 @@ reportlab==4.0.*
 requests==2.31.*
 sentry-sdk==1.30.*
 tqdm==4.66.*
-websockets==11.*
+websockets==12.*
 xlrd~=1.2.0  # do not update, 2.x does not support .xlsx, only .xls
 
 # deploy