Automatically watch helm subcharts when skipBuildDependencies is enabled

[pscarey]

Fixes #1347

Previously, the Helm deployer was set to ignore chart dependencies, so updating a sub chart didn't trigger a re-deploy in when running skaffold dev. This pull request removes that restriction, so that chart dependencies are included in the watch list.

[codecov-io]

Codecov Report

Merging #1371 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1371      +/-   ##
==========================================
+ Coverage   55.96%   56.03%   +0.07%     
==========================================
  Files         173      175       +2     
  Lines        7566     7616      +50     
==========================================
+ Hits         4234     4268      +34     
- Misses       2928     2940      +12     
- Partials      404      408       +4

Impacted Files	Coverage Δ
pkg/skaffold/deploy/helm.go	62.55% <100%> (+0.15%)	⬆️
pkg/skaffold/schema/validation/validation.go	100% <0%> (ø)	⬆️
pkg/skaffold/schema/versions.go	74.35% <0%> (ø)	⬆️
pkg/skaffold/build/kaniko/types.go
pkg/skaffold/build/kaniko/sources/localdir.go
pkg/skaffold/build/kaniko/sources/gcs.go
pkg/skaffold/build/kaniko/run.go
pkg/skaffold/build/kaniko/sources/sources.go
pkg/skaffold/build/kaniko/kaniko.go
pkg/skaffold/build/kaniko/secret.go
... and 12 more

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[balopat]

LGTM - I'm just going to confirm if there was an historical reason why it was not enabled...

[balopat]

@pscarey this is not going to be that easy seemingly.
#932
We run helm dep build on rebuilds that causes an infinite loop. Did you not run into this issue?

[pscarey]

Thanks for raising that issue.

I ran the existing go tests with only these changes, but am current successfully using #1368 in conjunction with this on our actual helm charts (as #1368 is required to run our charts).

Would you be happy if I paused this until we've completed the merge of #1368, then only allowed automatic watching of subcharts when the Helm skipDependencyBuild option is enabled? I will also document this caveat.

[pscarey]

The 'helm dep build' command modifies files in the charts directory of the main helm chart. By default any files in that directory are excluded from the watch list, but if skipBuildDependencies is enabled those files are now automatically included.

[nkubala]

I think this will work now that #1368 is in, @pscarey can you rebase please?

[pscarey]

@nkubala Have updated.

[nkubala]

@pscarey thanks for updating this, it looks good. would you mind adding a small section to the docs to briefly explain this? just want to make sure this doesn't get buried 👍

[pscarey]

@nkubala Hope the description is clear. Please add the docs-modifications label. Thanks.

addressed