use yarn instead of npm and add a script to ease the release process

README.md

@@ -52,10 +52,15 @@ using the Action, so be careful not to `git add` all the development dependencie
 you might have under your local `node_modules`. To release a new version of the
 Action the workflow should be the following:
 
+
 1. `npm install` to add all the dependencies, included development.
 1. `npm run test` to see everything works as expected.
-1. `npm build` to build the Action under the `./lib` folder.
+1. `npm build` 
 1. `rm -rf node_modules` to remove all the dependencies.
-1. `npm install --production` to add back **only** the runtime dependencies.
+1. `npm install --production` 
+1. `git add lib node_modules` to check in the code that matters.
+1. open a PR and request a review.
+
+1. `yarn run release` to build the Action under the `./lib` folder, and to add **only** the runtime dependencies under the `./node_modules` folder.
 1. `git add lib node_modules` to check in the code that matters.
 1. open a PR and request a review.