keps/sig-testing: declare 2420 implemented in v1.21

specifically:

- drop quote-wrapping

Author: spiffxp

keps/sig-testing/2420-reducing-kubernetes-build-maintenance/README.md

@@ -556,6 +556,7 @@ Major milestones might include:
 - 2020-02-08 - KEP Implementable [#2469](https://github.com/kubernetes/enhancements/pull/2469)
 - 2020-04-01 - KEP Alpha, Beta in Kubernetes 1.21
   - There is no distinct alpha/beta for this KEP, only alpha/beta (implemented at HEAD) vs stable (all supported branches)
+- 2020-08-16 - Retroactive implemented declaration
 
 See also PR listing: https://github.com/kubernetes/enhancements/issues/2420#issuecomment-791024902
 

keps/sig-testing/2420-reducing-kubernetes-build-maintenance/kep.yaml

@@ -6,8 +6,9 @@ authors:
 owning-sig: sig-testing
 participating-sigs:
   - sig-release
-status: implementable
+status: implemented
 creation-date: 2021-02-03
+last-updated: 2021-08-16
 reviewers:
   - dims
   - liggitt
@@ -21,18 +22,18 @@ see-also: []
 replaces: []
 
 # The target maturity stage in the current dev cycle for this KEP.
-stage: beta
+stage: stable
 
 # The most recent milestone for which work toward delivery of this KEP has been
 # done. This can be the current (upcoming) milestone, if it is being actively
 # worked on.
-latest-milestone: "v1.21"
+latest-milestone: v1.21
 
 # The milestone at which this feature was, or is targeted to be, at each stage.
 milestone:
-  alpha: "v1.21"
-  beta: "v1.21"
-  stable: "v1.23"
+  alpha: v1.21
+  beta: v1.21
+  stable: v1.23
 
 # these are N/A
 # The following PRR answers are required at alpha release