[website]: Update .asf.yaml to add "publish" configuration block (#4575)

Author: jiazhai

.asf.yaml

@@ -80,6 +80,9 @@ github:
     branch-4.15: {}
     branch-4.16: {}
 
+publish:
+  whoami: asf-site
+
 notifications:
   commits:      [email protected]
   issues:       [email protected]