ci: add pylint, but allow failure

.gitlab-ci.yml

@@ -36,6 +36,15 @@ test:mypy:
     - pip install -r requirements-types.txt --quiet
     - mypy app
 
+test:pylint:
+  script:
+    - cp config.yaml.example config.yaml
+    - apt update && apt install build-essential
+    - pip install -r requirements.txt --quiet
+    - pip install pylint --quiet
+    - pylint app
+  allow_failure: true
+
 pages:
   stage: deploy
   script: