skaffold find-configs should error if a too-new config file is found

[briandealwis]

I tried to launch the examples/helm-deployment within CC-VSC, which failed in a surprising way. In diagnosing the issue, it turns out that I was actually in integration/examples/helm-deployment and the skaffold.yaml had too new of an apiVersion. CC uses skaffold find-configs to find the configuration files, which in this case returns nothing:

$ skaffold version
v1.20.0
$ skaffold find-configs --output json
{}

As a result, CC-VSC then tried to do a skaffold init --analyze, which failed (due to Helm).

Expected behavior

skaffold find-configs should probably report all skaffold.yaml regardless of the apiVersion. It's possible a user is running an older version of Skaffold. Let the version error come up when they attempt to launch.

Information

• Skaffold version: 1.20.0
• Operating system: macos
• Installed via: Google Cloud SDK
• Contents of skaffold.yaml:
  http://github.com/GoogleContainerTools/skaffold/blob/master/integration/examples/helm-deployment/skaffold.yaml