promptYN = () => new Promise( ( resolve, reject ) => {
	prompt.message = '';
	prompt.start();
	prompt.get( [ 'y/n' ], ( err, result ) => {
		if ( err ) {
			return reject( err );
		}
		resolve( AFFIRMATIVE_RE.test( result[ 'y/n' ] ) );
	} );
} )
Helper method to request yes/no confirmation from the user, with some

@private
@returns {Promise} A promise that will resolve with a boolean true/false
indicating whether assent was given