ci: Use multiline chomp in YAML

It put the backslashes right into the bash command bash didn't really like that.
Bash escaped spaces and that lead to a bad command

.gitlab-ci.yml

@@ -87,11 +87,12 @@ push_dockerhub_registry:
     - docker push $DOCKERHUB_REGISTRY_IMAGE:$CI_COMMIT_TAG
     - docker push $DOCKERHUB_REGISTRY_IMAGE:latest
     # Push the readme to dockerhub
-    - docker run -v $PWD:/workspace \
-      -e DOCKERHUB_USERNAME="$DOCKERHUB_REGISTRY_USER" \
-      -e DOCKERHUB_PASSWORD="$DOCKERHUB_REGISTRY_PASSWORD" \
-      -e DOCKERHUB_REPOSITORY="$DOCKERHUB_REGISTRY_IMAGE" \
-      -e README_FILEPATH='/workspace/README.md' \
+    - >-
+      docker run -v $PWD:/workspace
+      -e DOCKERHUB_USERNAME="$DOCKERHUB_REGISTRY_USER"
+      -e DOCKERHUB_PASSWORD="$DOCKERHUB_REGISTRY_PASSWORD"
+      -e DOCKERHUB_REPOSITORY="$DOCKERHUB_REGISTRY_IMAGE"
+      -e README_FILEPATH='/workspace/README.md'
       peterevans/dockerhub-description:2
   only:
     refs: