ci(mergify): upgrade configuration to current format

Author: mergify[bot]

.mergify.yml

@@ -8,34 +8,28 @@ queue_rules:
       - "#approved-reviews-by >= 1"
       - base = main
     merge_method: merge
-    autosquash: true   
-
   - name: backport-apps-201.0-queue
     batch_size: 3
     queue_conditions:
       - "#approved-reviews-by >= 1"
       - base = maint-201.0
     merge_method: merge
-    autosquash: true   
-
   - name: backport-libs-0.251-queue
     batch_size: 3
     queue_conditions:
       - "#approved-reviews-by >= 1"
       - base = maint-libs-0.251
     merge_method: merge
-    autosquash: true   
-
 pull_request_rules:
   - name: automatic merge to main or backport branch
     conditions:
       - label = "merge"
       - label != "do-not-merge"
       - "#approved-reviews-by >= 1"
       - or:
-        - base = main
-        - base = maint-201.0
-        - base = maint-libs-0.251
+          - base = main
+          - base = maint-201.0
+          - base = maint-libs-0.251
     actions:
       queue: