Remove TypeScript

This removes TypeScript and all dependencies and only keeps a simple
Javascript file that does not have any dependencies and can be run
directly. There is not need for an NPM build any more and we just
call a shell script via Javascript.

With this, we no longer have to commit node_modules and Javascript
compiled from TypeScript code. Also, the shell script can easily be run
directly for local testing.

Signed-off-by: Reinhard Naegele <unguiculus@gmail.com>

action.yml

@@ -1,14 +1,16 @@
-name: "chart-releaser action"
-description: "Run the chart-releaser tool"
-author: "unguiculus"
+name: "GitHub Action for Helm Chart Releasing"
+description: "Release your Helm chart to a charts repo on GitHub Pages"
+author: "The Helm authors"
+branding:
+  color: blue
+  icon: check-circle
 inputs:
-  charts-dir:
+  charts_dir:
     description: The charts directory
     default: charts
-  charts-repo-url:
+  charts_repo_url:
     description: "The GitHub Pages URL to the charts repo (default: https://<owner>.github.io/<repo>)"
-  token:
-    description: The GitHub token
+    required: true
 runs:
   using: "node12"
-  main: "lib/main.js"
+  main: "main.js"