update conformance testing checklist requirement

Author: katcosgrove

keps/NNNN-kep-template/README.md

@@ -136,7 +136,7 @@ Items marked with (R) are required *prior to targeting to a milestone / release*
   - [ ] (R) Ensure GA e2e tests meet requirements for [Conformance Tests](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/conformance-tests.md) 
   - [ ] (R) Minimum Two Week Window for GA e2e tests to prove flake free
 - [ ] (R) Graduation criteria is in place
-  - [ ] (R) [all GA Endpoints](https://github.com/kubernetes/community/pull/1806) must be hit by [Conformance Tests](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/conformance-tests.md) 
+  - [ ] (R) [all GA Endpoints](https://github.com/kubernetes/community/pull/1806) must be hit by [Conformance Tests](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/conformance-tests.md) within one minor version of promotion to GA
 - [ ] (R) Production readiness review completed
 - [ ] (R) Production readiness review approved
 - [ ] "Implementation History" section is up-to-date for milestone