Move mergify to queue action

.mergify.yml

@@ -1,25 +1,46 @@
+queue_rules:
+  - name: default
+    conditions:
+    - check-success=doc (docs)
+    - check-success=doc (docs-gnocchi-web)
+    - check-success=check (pep8)
+    - check-success=test (py36, postgresql-file-upgrade-from-4.3)
+    - check-success=test (py36, mysql-file)
+    - check-success=test (py36, mysql-swift)
+    - check-success=test (py36, mysql-s3)
+    - check-success=test (py36, postgresql-file)
+    - check-success=test (py36, postgresql-swift)
+    - check-success=test (py36, postgresql-s3)
+    - check-success=test (py38, mysql-ceph-upgrade-from-4.3)
+    - check-success=test (py38, postgresql-file-upgrade-from-4.3)
+    - check-success=test (py38, mysql-file)
+    - check-success=test (py38, mysql-swift)
+    - check-success=test (py38, mysql-s3)
+    - check-success=test (py38, mysql-ceph)
+    - check-success=test (py38, postgresql-file)
+    - check-success=test (py38, postgresql-swift)
+    - check-success=test (py38, postgresql-s3)
+    - check-success=test (py38, postgresql-ceph)
+
 pull_request_rules:
   - name: automatic merge
     actions:
-      merge:
-        method: rebase
-        rebase_fallback: merge
+      queue:
+        method: merge
+        name: default
     conditions:
     - label!=work-in-progress
     - '#approved-reviews-by>=1'
     - check-success=doc (docs)
     - check-success=doc (docs-gnocchi-web)
-
     - check-success=check (pep8)
-
     - check-success=test (py36, postgresql-file-upgrade-from-4.3)
     - check-success=test (py36, mysql-file)
     - check-success=test (py36, mysql-swift)
     - check-success=test (py36, mysql-s3)
     - check-success=test (py36, postgresql-file)
     - check-success=test (py36, postgresql-swift)
     - check-success=test (py36, postgresql-s3)
-
     - check-success=test (py38, mysql-ceph-upgrade-from-4.3)
     - check-success=test (py38, postgresql-file-upgrade-from-4.3)
     - check-success=test (py38, mysql-file)
@@ -33,9 +54,9 @@ pull_request_rules:
 
   - name: automatic merge backports from Mergify
     actions:
-      merge:
-        method: rebase
-        rebase_fallback: merge
+      queue:
+        method: merge
+        name: default
     conditions:
     - base~=^stable/.*
     - label!=work-in-progress