* Viper keys are case insensitive.
This fixes an issue where import paths with uppercase (github.com/GoogleCloudPlatform 👀) were being canonicalized by Viper to all lowercase and the baseImageOverrides in `.ko.yaml` were failing to properly identify the base image.
I hit this in: https://github.com/tektoncd/pipeline/pull/2435 trying to opt some of the GCP images out of `:nonroot`.
This also adds some logging to a place where I see a lot of folks have issues with `ko` where we swallow an error. I hit it experimenting with variants on the `ko publish` import path, and added the logging to debug.
* Drop the new log statement
This hoists the publisher creation out of the loop for `ko publish` to
avoid needlessly resolving credentials multiple times.
This pulls the publisher creation outside of resolveFilesToWriter so we
can fail earlier if e.g. KO_DOCKER_REPO is unset, otherwise we start up
the kubectl goroutine and it would asynchronously fail with:
error: no objects passed to apply
