KEP-2862: Update BETA and GA graduation criteria.

Author: vinayakankugoyal

keps/sig-node/2862-fine-grained-kubelet-authz/README.md

@@ -95,6 +95,8 @@ tags, and then generate with `hack/update-toc.sh`.
       - [e2e tests](#e2e-tests)
   - [Graduation Criteria](#graduation-criteria)
     - [Alpha](#alpha)
+    - [Beta](#beta)
+    - [GA](#ga)
   - [Upgrade / Downgrade Strategy](#upgrade--downgrade-strategy)
   - [Version Skew Strategy](#version-skew-strategy)
 - [Production Readiness Review Questionnaire](#production-readiness-review-questionnaire)
@@ -621,6 +623,13 @@ in back-to-back releases.
 - Feature implemented behind a feature flag
 - Initial unit and integration tests completed and enabled
 
+#### Beta
+- Feature gate set to true by default
+- e2e tests added
+
+#### GA
+- Examples of real-world usage
+
 ### Upgrade / Downgrade Strategy
 
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