ci: add bandit job

.gitlab-ci.yml

@@ -1,5 +1,13 @@
 image: python:3.8-bullseye
 
+test:bandit:
+  script:
+      - cp config.yaml.example config.yaml
+      - apt update && apt install build-essential
+      - pip install -r requirements.txt --quiet
+      - pip install bandit --quiet
+      - bandit -r app
+
 test:mypy:
   script:
       - cp config.yaml.example config.yaml