ci(mergify): upgrade configuration to current format (#156)

Co-authored-by: Mergify <37929162+mergify[bot]@users.noreply.github.com>

.mergify.yml

@@ -1,33 +1,36 @@
-pull_request_rules:
-  - name: Merge dependency-update PRs
-    conditions:
+queue_rules:
+  - name: duplicated default from Merge PRs using label (rebase)
+    queue_conditions:
       - label=dependencies
       - base=master
-    actions:
-      queue:
-        name: default
-        method: squash
-
-  - name: Merge PRs using label (rebase)
-    conditions:
       - label=ready-to-merge-rebase
       - base=master
       - "#review-requested=0"
       - "#changes-requested-reviews-by=0"
       - "#review-threads-unresolved=0"
-    actions:
-      queue:
-        name: default
-        method: rebase
-
-  - name: Merge PRs using label (squash)
-    conditions:
+    merge_conditions: []
+    merge_method: rebase
+  - name: duplicated default from Merge PRs using label (squash)
+    queue_conditions:
+      - label=dependencies
+      - base=master
       - label=ready-to-merge-squash
       - base=master
       - "#review-requested=0"
       - "#changes-requested-reviews-by=0"
       - "#review-threads-unresolved=0"
+    merge_conditions: []
+    merge_method: squash
+  - name: default
+    queue_conditions:
+      - label=dependencies
+      - base=master
+    merge_conditions: []
+    merge_method: squash
+
+pull_request_rules:
+  - name: Merge PRs using label (rebase) + Merge PRs using label (squash) + Merge
+      dependency-update PRs
+    conditions: []
     actions:
       queue:
-        name: default
-        method: squash