dependabot: group action updates

This is the same grouping that is done
in core and OWS.

Author: pjonsson

.github/dependabot.yml

@@ -8,7 +8,11 @@ updates:
   - package-ecosystem: "github-actions" # See documentation for possible values
     directory: "/" # Location of package manifests
     schedule:
-      interval: "daily"
+      interval: "weekly"
+    groups:
+      actions-deps:
+        patterns:
+          - "*"
   - package-ecosystem: "docker"
     directory: "/docker"
     schedule: