ko should output more platform into for --platform=all

[mattmoor]

I see:

KO_DOCKER_REPO=docker.io/mattmoor ko resolve --platform=all -f test/test_images/helloworld/service.yaml 
2020/09/25 08:26:11 Using base debian:latest for ko://knative.dev/serving/test/test_images/helloworld
2020/09/25 08:26:14 Building knative.dev/serving/test/test_images/helloworld for amd64
2020/09/25 08:26:18 Building knative.dev/serving/test/test_images/helloworld for arm
2020/09/25 08:26:45 Building knative.dev/serving/test/test_images/helloworld for arm
2020/09/25 08:26:50 Building knative.dev/serving/test/test_images/helloworld for arm64
2020/09/25 08:27:17 Building knative.dev/serving/test/test_images/helloworld for 386

However, there is surely more detail to be had here.