Fix keps not passing new validation

Author: wojtek-t

keps/sig-auth/2907-secrets-store-csi-driver/kep.yaml

@@ -15,3 +15,9 @@ approvers:
   - "@mikedanese"
 status: implemented
 stage: stable
+
+latest-milestone: "v1.19"
+
+# The milestone at which this feature was, or is targeted to be, at each stage.
+milestone:
+  stable: "v1.22"

keps/sig-network/2829-gateway-api-to-k8s-io/kep.yaml

@@ -17,3 +17,6 @@ approvers:
 
 # The target maturity stage in the current dev cycle for this KEP.
 stage: alpha
+
+# This is out-of-tree and we provide milestone just to pass validation.
+latest-milestone: "v1.22"