Improved GitHub Action CI configuration.

Author: mgruner

.github/workflows/ci.yml

@@ -4,16 +4,13 @@ jobs:
   CI:
     runs-on: ubuntu-20.04
     container:
-      image: registry.zammad.com/docker/zammad-ci:stable
-      credentials:
-        username: ${{ secrets.ZAMMAD_DOCKER_REGISTRY_USERNAME }}
-        password: ${{ secrets.ZAMMAD_DOCKER_REGISTRY_PASSWORD }}
+      image: zammad/zammad-ci:latest
     services:
       postgresql:
-        image: registry.zammad.com/docker/zammad-postgresql:stable
-        credentials:
-          username: ${{ secrets.ZAMMAD_DOCKER_REGISTRY_USERNAME }}
-          password: ${{ secrets.ZAMMAD_DOCKER_REGISTRY_PASSWORD }}
+        image: postgres:10
+        env:
+          POSTGRES_USER: zammad
+          POSTGRES_PASSWORD: zammad
     env:
       ZAMMAD_PHP_API_CLIENT_UNIT_TESTS_URL: "http://localhost:3000"
       ZAMMAD_PHP_API_CLIENT_UNIT_TESTS_USERNAME: "admin@example.com"