Revive progress and warning logs (ko-build#203)

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

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

cmd/ko/main.go

@@ -16,13 +16,18 @@ package main
 
 import (
 	"log"
+	"os"
 
+	"github.com/google/go-containerregistry/pkg/logs"
 	"github.com/google/ko/pkg/commands"
 
 	"github.com/spf13/cobra"
 )
 
 func main() {
+	logs.Warn.SetOutput(os.Stderr)
+	logs.Progress.SetOutput(os.Stderr)
+
 	// Parent command to which all subcommands are added.
 	cmds := &cobra.Command{
 		Use:   "ko",

pkg/commands/config.go

@@ -52,13 +52,14 @@ func getBaseImage(platform string) build.GetBase {
 	}
 
 	return func(s string) (build.Result, error) {
+		s = strings.TrimPrefix(s, build.StrictScheme)
 		// Viper configuration file keys are case insensitive, and are
 		// returned as all lowercase.  This means that import paths with
 		// uppercase must be normalized for matching here, e.g.
 		//    github.com/GoogleCloudPlatform/foo/cmd/bar
 		// comes through as:
 		//    github.com/googlecloudplatform/foo/cmd/bar
-		ref, ok := baseImageOverrides[strings.ToLower(strings.TrimPrefix(s, build.StrictScheme))]
+		ref, ok := baseImageOverrides[strings.ToLower(s)]
 		if !ok {
 			ref = defaultBaseImage
 		}