Add action input to set download base url (#113)

* feat: add downloadBaseURL action input

* feat: downloadHelm and getHelmDownloadURL added baseURL function argument

* refactor: building the helm download url

* chore: format code

---------

Co-authored-by: Paul Vollmer <mail@paulvollmer.net>

action.yml

@@ -8,6 +8,10 @@ inputs:
    token:
       description: GitHub token. Required only if 'version' == 'latest'
       required: false
+   downloadBaseURL:
+      description: 'Set the download base URL'
+      required: false
+      default: 'https://get.helm.sh'
 outputs:
    helm-path:
       description: 'Path to the cached helm binary'