Update mergify for better branch name

Author: alpe

.mergify.yml

@@ -6,7 +6,7 @@ queue_rules:
 pull_request_rules:
   - name: backport patches to main branch
     conditions:
-      - base=releases/v0.42.x
+      - base=releases/v0.4x
       - label=backport/main
     actions:
       backport:
@@ -20,11 +20,11 @@ pull_request_rules:
       backport:
         branches:
           - releases/v0.3x
-  - name: backport patches to v0.42.x release branch
+  - name: backport patches to sdk47 release branch
     conditions:
       - base=main
-      - label=backport/v0.42.x
+      - label=backport/v0.4x
     actions:
       backport:
         branches:
-          - releases/v0.42.x
+          - releases/v0.4x