Update chart version

Signed-off-by: Derek Su <derek.su@suse.com>

deploy/chart/Chart.yaml

 apiVersion: v1
 description: Use HostPath for persistent local storage with Kubernetes
 name: local-path-provisioner
-version: 0.0.20
+version: 0.0.21
 appVersion: "v0.0.21"
 keywords:
   - storage