Update Knative Dependencies to Align with Pipelines

[danielhelfand]

Expected Behavior

To be able to deploy triggers without issues.

Actual Behavior

On some distributions of Kubernetes, the following error can occur due to the version of Knative dependencies used by triggers:

tekton-triggers-controller {"level":"fatal","logger":"controller","caller":"sharedmain/main.go:149","msg":"Version check failed","error │
│ ":"kubernetes version \"\" is not compatible, need at least \"v1.15.0\" (this can be overridden with the env var \"KUBERNETES_MIN_VERSI │
│ ON\")","stacktrace":"knative.dev/pkg/injection/sharedmain.MainWithConfig\n\tknative.dev/[email protected]/injectio │
│ n/sharedmain/main.go:149\nknative.dev/pkg/injection/sharedmain.MainWithContext\n\tknative.dev/[email protected]/in │
│ jection/sharedmain/main.go:114\nknative.dev/pkg/injection/sharedmain.Main\n\tknative.dev/[email protected]/injecti │
│ on/sharedmain/main.go:98\nmain.main\n\tgithub.com/tektoncd/triggers@/cmd/controller/main.go:32\nruntime.main\n\truntime/proc.go:203"}

The workaround is to set the KUBERNETES_MIN_VERSION environment variable on the deployments for the triggers controller/webhook to be the version of the cluster being used. This was also previously a problem for pipelines as well before tektoncd/pipeline#2721.

The error comes from how the server version is validated here, which has been updated in pipelines.

Is there any reason for building around the Knative dependencies currently used?

/kind bug

[dibyom]

Is there any reason for building around the Knative dependencies currently used?

Not that I'm aware of. We just need to bump our dependencies!