Adjusts required checks to the new structure (#1264)

more details can be found here https://github.com/apache/infrastructure-asfyaml/blob/main/README.md#branch-protection

Author: lukaszlenart

.asf.yaml

@@ -17,16 +17,18 @@ github:
   protected_branches:
     main:
       # contexts are the names of checks that must pass.
-      contexts:
-        - build
+      required_status_checks:
+        contexts:
+          - build
       required_pull_request_reviews:
         # it does not work because our github teams are private/secret, see INFRA-25666
         require_code_owner_reviews: false
         required_approving_review_count: 0
     release/struts-6-7-x:
       # contexts are the names of checks that must pass.
-      contexts:
-        - build
+      required_status_checks:
+        contexts:
+          - build
       required_pull_request_reviews:
         # it does not work because our github teams are private/secret, see INFRA-25666
         require_code_owner_reviews: false