ci(mergify): upgrade configuration to current format (#4138)

Co-authored-by: Mergify <37929162+mergify[bot]@users.noreply.github.com>

.mergify.yml

@@ -1,10 +1,11 @@
-pull_request_rules:
-  - name: Automatic merge using squash
-    conditions:
+queue_rules:
+  - name: default
+    queue_conditions:
       - "#approved-reviews-by>=1"
-    actions:
-      queue:
-        method: squash
+    merge_conditions: []
+    merge_method: squash
+
+pull_request_rules:
   - name: Automatic branch update
     conditions:
       - -conflict # skip PRs with conflicts
@@ -17,5 +18,9 @@ pull_request_rules:
     conditions:
       - merged
     actions:
-      delete_head_branch: 
+      delete_head_branch:
         force: true
+  - name: Automatic merge using squash
+    conditions: []
+    actions:
+      queue: