Ability to add '--skip-refresh' to "helm dependency build"

[cep21]

FEATURE REQUEST

What happened:

When running chart-testing against multiple charts, the command helm dependency build X is run for each chart. On each run, I see the following text

Hang tight while we grab the latest from your chart repositories...

We have many helm chart repositories and this refresh on each chart we test in our mono repo is the slowest part of our CI/CD since it involves external network calls. Helm has an option, --skip-refresh, that can be passed to dependency build. This will skip this refresh step and greatly speed up CI/CD in helm mono repo setups.

What you expected to happen:

An option to tell chart-testing to run the helm refresh once, at the start of the command, then run with --skip-refresh on each sub chart. This will make CI/CD fast by not running refresh on each chart, but only at the start.

How to reproduce it (as minimally and precisely as possible):

Run chart-testing against multiple charts at once.

[nazarewk]

I'd love to see this feature too, this is the culprit: https://github.com/helm/chart-testing/blob/0a093e464b884565148eb71dda6999de0c956b17/pkg/tool/helm.go#L39-L41