Define GA graduation criteria

Author: cici37

keps/sig-api-machinery/2876-crd-validation-expression-language/README.md

@@ -44,6 +44,7 @@
   - [Graduation Criteria](#graduation-criteria)
     - [Alpha](#alpha)
     - [Beta](#beta)
+    - [GA](#ga)
 - [Production Readiness Review Questionnaire](#production-readiness-review-questionnaire)
   - [Feature Enablement and Rollback](#feature-enablement-and-rollback)
   - [Rollout, Upgrade and Rollback Planning](#rollout-upgrade-and-rollback-planning)
@@ -1114,6 +1115,11 @@ We plan to add e2e test under api-machinery for crd expression validation:
 - Optimization on super-linear complexity growth
 - Adding metric of the latency of CEL evaluation for CRD evaluation
 
+#### GA
+
+- Formatted message
+- Scalability evaluation
+
 ## Production Readiness Review Questionnaire
 
 ### Feature Enablement and Rollback