fix: default to builder supported platform with a warning instead of erroring

[gsquared94]

Using Skaffold with the buildpacks builder on an M1 Mac against the minikube cluster, there are two scenarios:

1. User specifies the platform explicitly using --platform=linux/amd64.
   This was previously erroring out, due to Skaffold disallowing builds for a platform that doesn't match the active kubernetes cluster nodes. However, local clusters like minikube and docker-desktop on Apple M1 can run linux/amd64 images using qemu binfmt_misc extensions. So we changed this error condition to a warning message instead in fix: change error to warning for build platform mismatch with cluster node platform #7402.

2. Users don't specify platform explicitly
   In this case Skaffold selects the platform linux/arm64 based on the active kubernetes cluster node platform type. However, since buildpacks doesn't support building for this platform the build fails. We instead change this to a warning message and select the builder supported platforms instead. This is fixed in this PR.

[codecov]

Codecov Report

Merging #7659 (4a6c230) into main (290280e) will decrease coverage by 3.84%.
The diff coverage is 53.95%.

@@            Coverage Diff             @@
##             main    #7659      +/-   ##
==========================================
- Coverage   70.48%   66.63%   -3.85%     
==========================================
  Files         515      585      +70     
  Lines       23150    28080    +4930     
==========================================
+ Hits        16317    18711    +2394     
- Misses       5776     8008    +2232     
- Partials     1057     1361     +304     

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	55.93% <38.88%> (-20.54%)	⬇️
cmd/skaffold/app/cmd/verify.go	41.17% <41.17%> (ø)
... and 329 more

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more

[aaron-prindle]

LGTM!