Add mypy to GitLab CI

.gitlab-ci.yml

@@ -1,6 +1,14 @@
 image: python:3.8-bullseye
 
-test:
+test:mypy:
+  script:
+      - cp config.yaml.example config.yaml
+      - apt update && apt install build-essential
+      - pip install -r requirements.txt --quiet
+      - pip install -r requirements-types.txt --quiet
+      - mypy app
+
+test:docs:
   stage: test
   script:
   - cp config.yaml.example config.yaml