update .asf.yaml (#15780)

Author: RainYuY

.asf.yaml

@@ -34,15 +34,9 @@ github:
     # Enable projects for project management boards
     projects: true
   protected_branches:
-    master:
-      # only disable force push
-      foo: bar
-    3.0:
-      # only disable force push
-      foo: bar
-    3.1:
-      # only disable force push
-      foo: bar
+    master: {}
+    3.0: {}
+    3.1: {}
   labels:
     - java
     - rpc