Revive progress and warning logs

[jonjohnsonjr]

These got dropped when we pulled in:
google/go-containerregistry#481

Which doesn't log by default, and requires opting in.

Before:

$ ko publish -P ./cmd/ko/
2020/09/25 11:23:47 Using base gcr.io/distroless/static:nonroot for ko://github.com/google/ko/cmd/ko
2020/09/25 11:23:48 Building github.com/google/ko/cmd/ko for linux/amd64
2020/09/25 11:23:56 Publishing gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko:latest
2020/09/25 11:24:10 Published gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko@sha256:088f55132ffdea808364a21f9973b9e463c03b9bc1f8a33a80bbaa89a359f456
gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko@sha256:088f55132ffdea808364a21f9973b9e463c03b9bc1f8a33a80bbaa89a359f456

After:

$ ko publish -P ./cmd/ko/
2020/09/25 11:23:08 Using base gcr.io/distroless/static:nonroot for github.com/google/ko/cmd/ko
2020/09/25 11:23:10 Building github.com/google/ko/cmd/ko for linux/amd64
2020/09/25 11:23:17 Publishing gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko:latest
2020/09/25 11:23:17 existing blob: sha256:7438552acdc56e8eda4401142955d4860f25be2af6348aef4c0ddd0f4eeaa0af
2020/09/25 11:23:17 existing blob: sha256:3c2cba919283a210665e480bcbf943eaaf4ed87a83f02e81bb286b8bdead0e75
2020/09/25 11:23:17 existing blob: sha256:72164b581b02b1eb297b403bcc8fc1bfa245cb52e103a3a525a0835a58ff58e2
2020/09/25 11:23:17 existing blob: sha256:fa712d40dbb2c65903bbd9996c3cdb22e5a07eb18dce44c425335463c8b5daf1
2020/09/25 11:23:17 existing blob: sha256:4000adbbc3eb1099e3a263c418f7c1d7def1fa2de0ae00ba48245cda9389c823
2020/09/25 11:23:18 gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko:latest: digest: sha256:73de099249bf3269c7dd1fbf951b3f5d793e7ae0d1115fcd068802d0e897312e size: 910
2020/09/25 11:23:18 Published gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko@sha256:73de099249bf3269c7dd1fbf951b3f5d793e7ae0d1115fcd068802d0e897312e
gcr.io/jonjohnson-test/ko/github.com/google/ko/cmd/ko@sha256:73de099249bf3269c7dd1fbf951b3f5d793e7ae0d1115fcd068802d0e897312e

Also fixes Using base gcr.io/distroless/static:nonroot for ko://github.com/google/ko/cmd/ko, since we're fixing logs anyway.

[codecov-commenter]

Codecov Report

Merging #203 into master will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #203      +/-   ##
==========================================
- Coverage   37.82%   37.79%   -0.03%     
==========================================
  Files          33       33              
  Lines        1380     1381       +1     
==========================================
  Hits          522      522              
- Misses        768      769       +1     
  Partials       90       90              

Impacted Files	Coverage Δ
pkg/commands/config.go	15.27% <0.00%> (-0.22%)	⬇️

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