chore: group github actions updates (#7460)

Configure dependabot to group all github actions version updates into a single PR to reduce noise and to avoid errors from version mismatches (e.g. https://github.com/expressjs/express/actions/runs/33495271692/job/99815876650?pr=7445).

Author: Phillip9587

.github/dependabot.yml

@@ -4,6 +4,10 @@ updates:
     directory: /
     schedule:
       interval: monthly
+    groups:
+      github-actions:
+        patterns:
+          - "*"
 
   - package-ecosystem: npm
     directory: /
@@ -14,4 +18,4 @@ updates:
     open-pull-requests-limit: 10
     ignore:
       - dependency-name: "*"
-        update-types: ["version-update:semver-major"]
+        update-types: ["version-update:semver-major"]