move apiserver-identity to implementable

Author: roycaihw

keps/sig-api-machinery/1965-kube-apiserver-identity/README.md

@@ -30,11 +30,11 @@
 
 Items marked with (R) are required *prior to targeting to a milestone / release*.
 
-- [ ] (R) Enhancement issue in release milestone, which links to KEP dir in [kubernetes/enhancements] (not the initial KEP PR)
-- [ ] (R) KEP approvers have approved the KEP status as `implementable`
-- [ ] (R) Design details are appropriately documented
-- [ ] (R) Test plan is in place, giving consideration to SIG Architecture and SIG Testing input
-- [ ] (R) Graduation criteria is in place
+- [x] (R) Enhancement issue in release milestone, which links to KEP dir in [kubernetes/enhancements] (not the initial KEP PR)
+- [x] (R) KEP approvers have approved the KEP status as `implementable`
+- [x] (R) Design details are appropriately documented
+- [x] (R) Test plan is in place, giving consideration to SIG Architecture and SIG Testing input
+- [x] (R) Graduation criteria is in place
 - [ ] (R) Production readiness review completed
 - [ ] Production readiness review approved
 - [ ] "Implementation History" section is up-to-date for milestone
@@ -211,6 +211,8 @@ operations covered by [existing SLIs/SLOs]?**
 
 ## Implementation History
 
+- 2020-09-18: KEP introduced
+
 ## Alternatives
 
 ### Alternative 1: new API + storage TTL

keps/sig-api-machinery/1965-kube-apiserver-identity/kep.yaml

@@ -3,7 +3,7 @@ kep-number: 1965
 authors:
   - "@roycaihw"
 owning-sig: sig-api-machinery
-status: provisional
+status: implementable
 creation-date: 2020-09-02
 reviewers:
   - "@caesarxuchao"