chore: Add mergify backport to v0.46.x (#11501)

.github/labeler.yml

@@ -18,6 +18,8 @@
   - x/genutil/**/*
 "C:x/gov":
   - x/gov/**/*
+"C:x/group":
+  - x/group/**/*
 "C:x/mint":
   - x/mint/**/*
 "C:x/nft":

.mergify.yml

@@ -14,8 +14,16 @@ pull_request_rules:
         name: default
         method: squash
         commit_message_template: |
-           {{ title }} (#{{ number }})
-           {{ body }}
+          {{ title }} (#{{ number }})
+          {{ body }}
+  - name: backport patches to v0.46.x branch
+    conditions:
+      - base=master
+      - label=backport/0.46.x
+    actions:
+      backport:
+        branches:
+          - release/v0.46.x
   - name: backport patches to v0.45.x branch
     conditions:
       - base=master