ci(Mergify): configuration update

Signed-off-by: Alex Zaytsev <null>

Author: hazzik

.mergify.yml

@@ -0,0 +1,10 @@
+pull_request_rules:
+  - name: Backport patches to the release branch and assign to original author
+    conditions:
+      - label = backport
+    actions:
+      backport:
+        branches:
+          - "5.5.x"
+        assignees:
+          - "{{ author }}"