chore(merge-queue): adding a new merge queue to tackle priority PR (#…

…33294)

### Issue # (if applicable)

Closes NA.

### Reason for this change

Adding a new merge queue to handle PRs that include a single commit like [PR with custom resource](#32904) changes that causes issue while releasing with other changes.


### Description of changes

Update mergify.yml to add new merge queue.

### Describe any new or updated permissions being added

No permissions related changes

### Description of how you validated changes

yarn build
yarn test

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

.mergify.yml

@@ -21,12 +21,32 @@ queue_rules:
       {{ body }}
 
   - name: default-squash
+    update_method: merge
+    merge_method: squash
+    conditions:
+      - base!=release
+      - -title~=(WIP|wip)
+      - -label~=(blocked|do-not-merge|no-squash|priority-pr)
+      - -merged
+      - -closed
+      - "#approved-reviews-by>=1"
+      - -approved-reviews-by~=author
+      # This is important! It makes the PR Linter work.
+      - "#changes-requested-reviews-by=0"
+      - status-success~=AWS CodeBuild us-east-1
+      - status-success=validate-pr
+    commit_message_template: |-
+      {{ title }} (#{{ number }})
+      {{ body }}
+
+  - name: priority-squash
     update_method: merge
     merge_method: squash
     conditions:
       - base!=release
       - -title~=(WIP|wip)
       - -label~=(blocked|do-not-merge|no-squash)
+      - label~=priority-pr
       - -merged
       - -closed
       - "#approved-reviews-by>=1"