feat: Add additional-values-files input to setup-cf action

[ZPascal]

The cf-java-client wants a validation build against the CAPI release that matches the CC API version it supports. The action can deploy only what versions.yaml specifies, or the latest develop versions when use-latest-versions is set.

This adds an optional additional-values-files input: a comma-separated list of Helmfile values files that is passed to make up as ADDITIONAL_VALUES_FILES and merged last. Callers can override any value, not just CAPI, e.g.:

charts:
  capi:
    version: 1.222.0

Relative paths are resolved against the calling workflow's workspace. By default the input is empty, so nothing changes for existing users.

This replaces the earlier, CAPI-specific capi-version input, following review feedback.

[pbusko]

I believe it would be better and more fitting to the reusable action scenario to open up a possibility to simply provide a custom Helmfile values, as described in https://github.com/cloudfoundry/kind-deployment#using-the-setup-cf-github-action

Any caller would be able to have a yaml file with:

charts:
  capi:
    version: x.x.x

and won't be limited only to capi, such flag feels oddly specific without possibility to override version of all the other deployments

[ZPascal]

I believe it would be better and more fitting to the reusable action scenario to open up a possibility to simply provide a custom Helmfile values, as described in https://github.com/cloudfoundry/kind-deployment#using-the-setup-cf-github-action

Any caller would be able to have a yaml file with:

charts:
  capi:
    version: x.x.x

and won't be limited only to capi, such flag feels oddly specific without possibility to override version of all the other deployments

Makes sense, a capi-only flag doesn't scale. I dropped capi-version and added additional-values-files, which delivers the information into the make up call.