github: update mergify.yml to new style

Mergify has not been working for weeks as they removed support for the
deprecated style we were relying on. This is my first attempt to
update it to the new style.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

.github/mergify.yml

@@ -1,5 +1,27 @@
 ---
+defaults:
+  actions:
+    queue:
+      name: default
+      method: rebase
+      rebase_fallback: merge
+      update_method: rebase
+
+# each test should be listed separately, do not use regular expressions:
+# https://docs.mergify.io/conditions.html#validating-all-status-check
+# Until mergify allows us to have default conditions, we will need to
+# repeat this list in a few places.
+queue_rules:
+  - name: default
+    conditions:
+      - check-success=check
+      - check-success=dpulls
+      - check-success=test-suite (nautilus)
+      - check-success=test-suite (octopus)
+      - check-success=test-suite (pacific)
+
 pull_request_rules:
+  # Clearing approvals after content changes
   - name: remove outdated approvals
     conditions:
       - base=master
@@ -7,6 +29,7 @@ pull_request_rules:
       dismiss_reviews:
         approved: true
         changes_requested: false
+  # Our auto merge rules
   - name: automatic merge
     conditions:
       - label!=do-not-merge
@@ -15,8 +38,7 @@ pull_request_rules:
       - "#changes-requested-reviews-by=0"
       - status-success=check
       - status-success=dpulls
-      # each test should be listed separately, do not use regular expressions:
+      # See above
-      # https://docs.mergify.io/conditions.html#validating-all-status-check
       - status-success=test-suite (nautilus)
       - status-success=test-suite (octopus)
       - status-success=test-suite (pacific)
@@ -32,13 +54,10 @@ pull_request_rules:
           - "#approved-reviews-by>=1"
           - "updated-at<10 days ago"
     actions:
-      merge:
+      queue: {}
-        method: rebase
-        rebase_fallback: merge
-        strict: smart
-        strict_method: rebase
       dismiss_reviews: {}
       delete_head_branch: {}
+  # Conflict resolution prompt
   - name: ask to resolve conflict
     conditions:
       - conflict