ci(mergify): upgrade configuration to current format (#10921)

* ci(mergify): upgrade configuration to current format

* fixup! ci(mergify): upgrade configuration to current format

---------

Co-authored-by: Mergify <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: brandon s allbery kf8nh <allbery.b@gmail.com>

.github/mergify.yml

@@ -14,17 +14,17 @@ priority_rules:
     conditions:
       - 'base~=^3\.'
       - 'label!=backport'
-    priority: 2500
+    priority: 2700
 
   - name: priority for queue `default`
     conditions:
       - queue-name=default
-    priority: 2250
+    priority: 2500
 
   - name: priority for queue `squash-merge`
     conditions:
       - queue-name=squash-merge
-    priority: 2250
+    priority: 2500
 
 pull_request_rules: