asf.yaml format update as syntax was out-of-date (#353)

Co-authored-by: Glynn Bird <glynnbird@apache.org>

Author: glynnbird

.asf.yaml

@@ -7,5 +7,8 @@ github:
     - nano
     - nodejs
   protected_branches:
-    main
+    main:
+      required_status_checks:
+        # strict means "Require branches to be up to date before merging".
+        strict: true