Add CODECOV token to CI (#3285)

We did not push code coverage from the master branch
since a while. Try to add a Codecov token, to get back on
track.

Author: gerzse

.github/workflows/integration.yaml

@@ -25,6 +25,7 @@ permissions:
 
 env:
   REDIS_STACK_IMAGE: redis/redis-stack-server:7.4.0-rc1
+  CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
 jobs:
   dependency-audit: