Update .gitlab-ci.yml file with --provenance=false

see https://dev.funkwhale.audio/funkwhale/infrastructure/infra/-/issues/71

.gitlab-ci.yml

@@ -520,6 +520,7 @@ docker:
           --set *.cache-from=type=registry,ref=$DOCKER_CACHE_IMAGE:$CI_COMMIT_BRANCH,oci-mediatypes=false
           --set *.cache-to=type=registry,ref=$DOCKER_CACHE_IMAGE:$CI_COMMIT_BRANCH,mode=max,oci-mediatypes=false
           --push
+          --provenance=false
 
     - if: $CI_PIPELINE_SOURCE == "merge_request_event" && $CI_PROJECT_NAMESPACE == "funkwhale"
       # We don't provide priviledged runners to everyone, so we can only build docker images in the funkwhale group