add gcloud auth

[shashankkoppar]

selected worker: concourseci-worker-1
Initializing kubectl access using gcloud service account file
Activated service account credentials for: [concourse@iam.gserviceaccount.com]
Updated property [core/account].
Updated property [core/project].
Fetching cluster endpoint and auth data.
kubeconfig entry generated for test.
Initializing helm...

this is how it looks in console output, have tested with concourse pipeline, works fine.

[Typositoire]

I'll merge it as latest and tag it when I have 5 minutes my concourse pipeline for tagging doesn't seem to be working right now xD

[shashankkoppar]

Thanks man, appreciate it!