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

.dockerignore

@@ -1,4 +1,8 @@
-# CI cache folder storing docker images
-ci-exports/
-
+.idea
+.git
 .gitlab-ci.yml
+.vscode
+
+# CI cache folder storing docker images
+ci-exports
+

.gitlab-ci.yml

@@ -23,18 +23,18 @@ variables:
   # Use TLS https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#tls-enabled
   DOCKER_HOST: tcp://docker:2376
 
+services:
+  - docker:19.03.12-dind
+
 .docker_cache:
   cache:
+    # The same key should be used across branches
     key: "$CI_COMMIT_REF_SLUG"
     paths:
       - ci-exports/*.tar
 
-services:
-  - docker:19.03.12-dind
-
-
 # Make sure we can build a docker image
-# It's pushed to the pipeline-local registry which acts as a cache
+# It's cached for later jobs
 build_docker:
   extends:
     - .docker_cache
@@ -62,11 +62,13 @@ push_ci_registry:
     - docker push $CI_REGISTRY_IMAGE:latest
   only:
     refs:
-      - master
+      # Make sure to protect these tags!
+      - /^v(\d+\.){2,3}\d+$/
+      - /.+-release$/
     variables:
+      - $CI_REGISTRY
       - $CI_REGISTRY_USER
       - $CI_REGISTRY_PASSWORD
-      - $CI_REGISTRY
       - $CI_REGISTRY_IMAGE
 
 # Publishes the cached image to docker
@@ -84,12 +86,21 @@ push_dockerhub_registry:
     - docker tag $CI_REGISTRY_IMAGE:latest $DOCKERHUB_REGISTRY_IMAGE:latest
     - 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'
+      peterevans/dockerhub-description:2
   only:
     refs:
-#      - master
-      - tags
+      # Make sure to protect these tags!
+      - /^v(\d+\.){2,3}\d+$/
+      - /.+-release$/
     variables:
+      - $DOCKERHUB_REGISTRY
       - $DOCKERHUB_REGISTRY_USER
       - $DOCKERHUB_REGISTRY_PASSWORD
-      - $DOCKERHUB_REGISTRY
       - $DOCKERHUB_REGISTRY_IMAGE