preBuild function
Implementation
Future preBuild(Directory projectDir) async {
// Run build
// print('Running `dart run build_runner build`...');
print(darkGray.wrap('\$ dart run build_runner build'));
var build = await Process.start("dart", ['run', 'build_runner', 'build'],
workingDirectory: projectDir.absolute.path,
mode: ProcessStartMode.inheritStdio);
var buildCode = await build.exitCode;
if (buildCode != 0) throw Exception('Failed to pre-build resources.');
}