add an option to override package path

[developer-guy]

In the meantime, the default location for the package path is .cr-release-packages¹, which is a path to a directory with chart packages², and we don't have an input option to override this path. It'd be nice if we could override this path via an input option.

cc: @cpanato

Footnotes

1. https://github.com/helm/chart-releaser-action/blob/main/cr.sh#L261 ↩

2. https://github.com/helm/chart-releaser#create-github-releases-from-helm-chart-packages ↩