Turns out I broke this.  Thanks to @bobcatfish for reporting the issue.

With this change:
```
ko resolve -Pf cmd/ko/test/test.yaml > /dev/null
2020/05/04 08:44:35 Using base gcr.io/distroless/static:nonroot for github.com/google/ko/cmd/ko/test
2020/05/04 08:44:36 Building github.com/google/ko/cmd/ko/test
2020/05/04 08:44:37 Publishing gcr.io/mattmoor-knative/github.com/google/ko/cmd/ko/test:latest
2020/05/04 08:44:39 Published gcr.io/mattmoor-knative/github.com/google/ko/cmd/ko/test@sha256:ee655510172b429dbce619fc69677621d71cb824cbbf2a21746d700127257ec4
```

I can cut v0.5.1 once this lands.