Migrate Triggers e2e test to kind

Follows the guide in docs/kind-e2e.md with a couple of changes to match the current pipeline e2e tests:

1. Use latest builder image for the time being
2. Adds a `pipeline-kind-e2e: "true"` label that is used for podAntiAffinity -
we don't want multiple kind jobs running on the same nodes.

Part of tektoncd/triggers#1475

Signed-off-by: Dibyo Mukherjee <dibyo@google.com>