Support Google Secret Manager version

[chaodaiG]

Currently gsm controller always pull from latest version, which is not ideal, should make it configurable, so that when there is a new version pushed, user can force controller pull the new version by updating the version field in the k8s cluster secret metadata. This is an alternative solution for #5 as well

[chaodaiG]

@rawlingsj , if this repo is open to collaboration I won't mind contribute

[caddac]

Would love to see this feature.

[chaodaiG]

Sorry forgot to circle back here. I have decided to use https://github.com/external-secrets/kubernetes-external-secrets instead, which works pretty well for us so far