ci(Mergify): configuration update (#27329)

Author: woody-apple

.mergify.yml

@@ -0,0 +1,13 @@
+pull_request_rules:
+  - name: Automatic merge on PullApprove
+    conditions:
+      - "#approved-reviews-by>=1"
+      - "#review-threads-unresolved=0"
+      - "-draft"
+      - or:
+        - "check-success=pullapprove"
+        - "check-skipped=pullapprove"
+        - "check-neutral=pullapprove"
+    actions:
+      merge:
+        method: squash