Add linting CI

.gitlab-ci.yml

 ---
 stages:
   - linting
-# Change pip's cache directory to be inside the project directory since we can
-# only cache local items.
-variables:
-  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
+
 cache:
   paths:
     - .cache
+
 ansible-lint:
   stage: linting
-  image: registry.gitlab.com/pipeline-components/ansible-lint:latest
-  before_script:
-    - pip3 install yamllint
+  image:
+    name: registry.gitlab.fachschaften.org/fsi-ansible/ci-docker-image:latest
+    entrypoint: [""]
   script:
-    - ansible-lint .
+    - ansible-lint -v --offline