add pylint (#15)

Reviewed-on: #15
Co-authored-by: Michael Grote <michael.grote@posteo.de>
Co-committed-by: Michael Grote <michael.grote@posteo.de>

.woodpecker/lint.yml

@@ -17,15 +17,16 @@ steps:
         evaluate: 'CI_COMMIT_AUTHOR_EMAIL != "renovate@mgrote.net"'
 
   pylint:
-    image: wpengine/pylint:terraform-1.8.2
+    image: "registry.mgrote.net/pylint:master"
     commands:
-      - pylint .
+      - pip3 install --no-cache-dir --break-system-packages -r requirements.txt
+      - pylint app.py
     when:
       - event: [push, pull_request]
         evaluate: 'CI_COMMIT_AUTHOR_EMAIL != "renovate@mgrote.net"'
 
   shellcheck:
-    image: "koalaman/shellcheck-alpine:v0.10.0"
+    image: koalaman/shellcheck-alpine:v0.10.0
     commands:
       - |
         find . -type f -not -path './.git/*' -not -path './collections/*' -exec file {} \; | while IFS= read -r line; do