fix: Fill IMAGE_TAG,etc on Docker builds

[0xADD1E]

Fixes: #4295

Description
Docs have long stated that these fields are available when using the local docker builder. This makes is to they actually are.

[aaron-prindle]

Thanks for the PR here! Can you rebase this PR, I think recently one of the issues seen in the tests:

panic: runtime error: index out of range [0] with length 0 [recovered]
	panic: runtime error: index out of range [0] with length 0

was fixed -
#7774

Additionally I believe there are some legitimate test failures where some expected values in tests might have to be changed in relation to the change made here. To run the full set of unit tests locally you can use make test. After we get these tests green we should be able to merge this!

[0xADD1E]

Right - so finally got a chance to get back around to this. Looks like it was just "used to be mocking EvalBuildArgs (as we were only using EvalBuildArgs) but need to also mock EvalBuildArgsWithEnv in some places"

It does feel like there should be a more elegant way of doing this, particularly with the caching bits (perhaps using EvalBuildArgsWithEnv everywhere? That's not how Kaniko is doing it though) -- but I don't think I have a complete enough picture to know exactly what that would be.

In the mean while, I believe the tests should be passing, and the docs match the actual behaviour

[codecov]

Codecov Report

Merging #7788 (fbf342f) into main (290280e) will decrease coverage by 3.91%.
The diff coverage is 53.59%.

@@            Coverage Diff             @@
##             main    #7788      +/-   ##
==========================================
- Coverage   70.48%   66.57%   -3.92%     
==========================================
  Files         515      593      +78     
  Lines       23150    28696    +5546     
==========================================
+ Hits        16317    19104    +2787     
- Misses       5776     8177    +2401     
- Partials     1057     1415     +358     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/credits/export.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	40.90% <0.00%> (-12.94%)	⬇️
cmd/skaffold/app/cmd/test.go	44.44% <0.00%> (ø)
cmd/skaffold/skaffold.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/inspect_tests.go	62.50% <14.28%> (-1.14%)	⬇️
cmd/skaffold/app/cmd/render.go	35.48% <18.18%> (-5.90%)	⬇️
cmd/skaffold/app/cmd/lsp.go	28.12% <28.12%> (ø)
cmd/skaffold/app/cmd/run.go	64.28% <33.33%> (-9.63%)	⬇️
cmd/skaffold/app/cmd/fix.go	56.41% <37.50%> (-20.07%)	⬇️
cmd/skaffold/app/cmd/verify.go	41.17% <41.17%> (ø)
... and 362 more

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[aaron-prindle]

Thanks so much for your work here @0xADD1E! Re:

It does feel like there should be a more elegant way of doing this, particularly with the caching bits (perhaps using EvalBuildArgsWithEnv everywhere? That's not how Kaniko is doing it though) -- but I don't think I have a complete enough picture to know exactly what that would be.

I've created an issue - #7824 to explore refactoring this as I agree.

Tests look good now, enabling auto-merge! Thanks again!

[aaron-prindle]

LGTM!