Merge pull request kubernetes#4135 from zshihang/master

KEP-2799: update latest-milestone to 1.28

Author: k8s-ci-robot

keps/sig-auth/2799-reduction-of-secret-based-service-account-token/kep.yaml

@@ -13,7 +13,7 @@ reviewers:
 approvers:
   - "@liggitt"
 stage: beta
-latest-milestone: "v1.27"
+latest-milestone: "v1.28"
 milestone:
   beta: "v1.24"
   stable: "v1.26"