gke-helmfile-deployment.sh is fragile and may not work for new helmfiles.

[willgraf]

Describe the bug
The gke-helmfile-deployment.sh will parse every helmfile in conf/helmfile.d, looking for the first "name" field it finds which IS NOT preceded by "stable". This is pretty fragile, as if there is a repositories field with a different name (or even stable without quotes), it will pick the repository name instead of the deployment name.

To Reproduce

1. Edit any helmfile with a repositories field and change the name from "stable" to anything else.
2. Run the gke-helmfile-deployment.sh script.
3. Check that it will have failed to deploy that resource (kubectl get po).

Expected behavior
helmfiles should be deployed even if they have a repository name that is not "stable".

Additional context
This was discovered when attempting to upgrade the redis helm chart to the bitnami helm repo. This seems like a good opportunity to fix the script and tackle #206

[willgraf]

Fixed by #300 in stable.