Merge pull request kubernetes#1430 from kevtaylor/kep/VolumeSubpathEnvExpansion-implemented

Move VolumeSubpathEnvExpansion to implemented

Author: k8s-ci-robot

keps/sig-storage/20181029-volume-subpath-env-expansion.md

@@ -15,8 +15,8 @@ approvers:
   - "@msau42"
 editor: TBD
 creation-date: 2018-10-29
-last-updated: 2018-03-04
-status: implementable
+last-updated: 2020-01-03
+status: implemented
 see-also:
   - n/a
 replaces: