Update ci (#44)

* + ghcr.io links

* update ci

* more cache moves

* fix cache move after compose test

* output image

* update description and don't login on PR's

* dependabot: actions

.github/dependabot.yml

@@ -1,8 +1,14 @@
 version: 2
 updates:
-- package-ecosystem: docker
-  directory: "/"
-  schedule:
-    interval: monthly
-    time: '02:00'
-  open-pull-requests-limit: 10
+  - package-ecosystem: docker
+    directory: "/"
+    schedule:
+      interval: monthly
+      time: "02:00"
+    open-pull-requests-limit: 10
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: monthly
+      time: "03:00"