Incorporate Cloud Deploy automations

[markmandel]

Details: https://cloud.google.com/deploy/docs/automation

Two thoughts for this:

1. On Agones installation, automate rollouts to clusters, if the first one succeeds, wait 5m (? would probably make this longer in production - an hour, to wait for problems?)
2. On game server rollouts - probably the same. It's a shame we can't test if a new Fleet update/installation has succeeded or not yet, but we can assume that some kind of alerting could catch that.

[markmandel]

Closing this since @abmarcum did this!