Enhance dependabot configuration to group GitHub Actions updates and ignore specific non-versioned actions

Author: Ankitsinghsisodya

.github/dependabot.yml

@@ -4,3 +4,11 @@ updates:
     directory: "/"
     schedule:
       interval: "weekly"
+    groups:
+      github-actions:
+        patterns:
+          - "*"
+    ignore:
+      # Following actions aren't versioned
+      - dependency-name: "chainguard-dev/actions/*"
+      - dependency-name: "knative/actions/*"