This updates the `actions/setup-node` action to version 2.2.2 and takes advantage of the cache feature now built in. This removes the need for an additional step using `actions/cache` to cache NPM dependencies.
The cache key used will be `${{ runner.os }}-npm-${{ hashFiles('') }}`, which matches the recommendation in the `actions/cache` documentation and the key currently in use in the WordPress workflows.
Props gziolo.
Fixes#53584.
Built from https://develop.svn.wordpress.org/trunk@51341
git-svn-id: http://core.svn.wordpress.org/trunk@50950 1a063a9b-81f0-0310-95a4-ce76da25c4cd