ci(mergify): upgrade configuration to current format

.mergify.yml

@@ -1,26 +1,26 @@
 queue_rules:
   - name: default
-    conditions:
+    queue_conditions:
       - base=master
       - label="merge-when-passing"
       - label!="work-in-progress"
       - "approved-reviews-by=@flux-framework/core"
       - "#approved-reviews-by>0"
       - "#changes-requested-reviews-by=0"
       - -title~=^\[*[Ww][Ii][Pp]
-
-pull_request_rules:
-  - name: rebase and merge when passing all checks
-    conditions:
+    merge_conditions:
       - base=master
       - label="merge-when-passing"
       - label!="work-in-progress"
       - "approved-reviews-by=@flux-framework/core"
       - "#approved-reviews-by>0"
       - "#changes-requested-reviews-by=0"
       - -title~=^\[*[Ww][Ii][Pp]
+    merge_method: merge
+    update_method: rebase
+
+pull_request_rules:
+  - name: refactored queue action rule
+    conditions: []
     actions:
       queue:
-        name: default
-        method: merge
-        update_method: rebase