Allow for remote kustomize bases

[jmcclell]

Fixes #2082

Kustomize will error if it can't find a base dependency, so it's safe for
Skaffold to assume that any base file that does not exist locally is intended
to be a remote path that can be ignored since Skaffold can't monitor remote
paths for changes.

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[jmcclell]

I've signed the CLA.

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[balopat]

This looks great, thank you!
Can you add one more testcase for the existing base case?

[codecov]

Codecov Report

Merging #2269 into master will increase coverage by 0.01%.
The diff coverage is 100%.

Impacted Files	Coverage Δ
pkg/skaffold/deploy/kustomize.go	73.52% <100%> (-0.67%)	⬇️
pkg/skaffold/jib/jib.go	78.49% <0%> (+1.07%)	⬆️

[jmcclell]

Added additional requested test case.

Test was added \o/

[matti]

but weren't bases just removed from kustomize?

[matti]

like they are replaced with ordered resources

[jmcclell]

@matti is apparently correct! I am not sure if remote resources are still supported, but this code will need to be modified to support the new version's implementation. Another issue can be opened for that, but here's the relevant documentation for the change for everyone's edification: https://github.com/kubernetes-sigs/kustomize/blob/dc433e12fb7063c57fec74e3ee0a24587c8ca84b/docs/v2.1.0.md#field-changes--deprecations

[dgageot]

Could you open another issue. That would be awesome!