copyFiles(configs) {
        webpackConfig.copyFiles(configs);

        return this;
    }
Copy files or folders to the build directory.

For example:

```
// Copy the content of a whole directory and its subdirectories
Encore.copyFiles({ from: './assets/images' });

// Only copy files matching a given pattern
Encore.copyFiles({ from: './assets/images', pattern: /\.(png|jpg|jpeg)$/ })

// Set the path the files are copied to
Encore.copyFiles({
    from: './assets/images',
    pattern: /\.(png|jpg|jpeg)$/,
    // to path is relative to the build directory
    to: 'images/[path][name].[ext]'
})

// Version files
Encore.copyFiles({
    from: './assets/images',
    to: 'images/[path][name].[hash:8].[ext]'
})

// Add multiple configs in a single call
Encore.copyFiles([
    { from: './assets/images' },
    { from: './txt', pattern: /\.txt$/ },
]);

// Set the context path: files will be copied
// into an images/ directory in the output dir
Encore.copyFiles({
    from: './assets/images',
    to: '[path][name].[hash:8].[ext]',
    context: './assets'
});
```

Notes:
     No transformation is applied to the copied files (for instance
       copying a CSS file won't minify it)

Supported options:
     - {string} from (mandatory)
             The path of the source directory (mandatory)
     - {RegExp|string} pattern (default: all files)
             A regular expression (or a string containing one) that
             the filenames must match in order to be copied
     - {string} to (default: [path][name].[ext])
             Where the files must be copied to. You can add all the
             placeholders supported by the file-loader.
             https://github.com/webpack-contrib/file-loader#placeholders
     - {boolean} includeSubdirectories (default: true)
             Whether or not the copy should include subdirectories.
     - {string} context (default: path of the source directory)
             The context to use as a root path when copying files.

@param {CopyFilesOptions|CopyFilesOptions[]} configs
@returns {Encore}