chore: update gitlab-ci component reference

Related: #4 (closed)

composer.json

@@ -20,7 +20,7 @@
         "email": "support@pcsg.de"
     },
     "require": {
-        "quiqqer/quiqqer": ">=1.6|dev-master|dev-dev"
+        "quiqqer/core": "^2"
     },
     "suggest": {
         "quiqqer/blog": "Create your own online diary. With the provided page types, managing and creating your own blog is no longer a problem.",
@@ -73,4 +73,4 @@
         "dev:init:tools": "Install all developer tools (requires PHIVE)",
         "dev:init:git-hooks": "Install all git hooks (may require tools to be installed)"
     }
-}
\ No newline at end of file
+}