ci(mergify): upgrade configuration to current format

Signed-off-by: Ken Dreyer <kdreyer@redhat.com>

Author: mergify[bot]

.mergify.yml

@@ -1,23 +1,23 @@
 queue_rules:
   - name: default
-    conditions:
+    queue_conditions:
+      - author=ktdreyer
       - status-success=tox27
       - status-success=tox (3.6, ubuntu-20.04)
       - status-success=tox (3.9, ubuntu-latest)
       - status-success=integration-tests (ga)
       - status-success=test-collection
-
-pull_request_rules:
-  - name: automatic merge for master when CI passes
-    conditions:
-      - author=ktdreyer
+      - base=master
+    merge_conditions:
       - status-success=tox27
       - status-success=tox (3.6, ubuntu-20.04)
       - status-success=tox (3.9, ubuntu-latest)
       - status-success=integration-tests (ga)
       - status-success=test-collection
-      - base=master
+    merge_method: rebase
+
+pull_request_rules:
+  - name: automatic merge for master when CI passes
+    conditions: []
     actions:
       queue:
-        name: default
-        method: rebase