Release v0.2.0

Adds Helm charts to repository that can be installed via Helm 3:

> helm repo add nats https://nats-io.github.io/k8s/helm/charts/
> helm repo update

> helm repo list
NAME          	URL 
nats          	https://nats-io.github.io/k8s/helm/charts/

> helm install my-nats nats/nats
> helm install my-stan nats/stan --set stan.nats.url=nats://my-nats:4222