Files will not be rebuilt if files in the entrypoint have been deleted

[w0rp]

Consider an entrypoint for webpack with an Array of files like so:

files: ['foo.js', 'bar.js']

If you first build with webpack, remove foo.js, and then build again, webpack will exit without building the file again, if this plugin is installed. This plugin should instead force files to be rebuilt again if any of the files are missing, and then clear the cache, so that an error can be printed for the missing file, and then files can be built again after the file has been removed from the files Array.