Add graduation criteria for alpha

Author: gjkim42

keps/sig-network/2595-expanded-dns-config/README.md

@@ -129,6 +129,11 @@ DNS configuration
 
 ### Graduation Criteria
 
+#### Alpha
+
+- Implement the feature
+- Add appropriate unit tests
+
 #### Alpha -> Beta Graduation
 
 - Address feedback from alpha