Fix authorization error when writting cache for the build (pull_request)

.github/workflows/docker-publish.yml

@@ -78,7 +78,7 @@ jobs:
             env.azul_docker_registry,
             env.azul_docker_elasticsearch_image
           ) }}"
-          cache-to: "${{ format(
+          cache-to: "${{ github.event_name == 'pull_request' && '' || format(
             'type=registry,ref={0}{1}_buildcache,mode=max',
             env.azul_docker_registry,
             env.azul_docker_elasticsearch_image