processMainActivity method 
    
    
    
  Implementation
  Future<void> processMainActivity(File path, String type) async {
  var extension = type == 'java' ? 'java' : 'kt';
  print('Project is using $type');
  print('Updating MainActivity.$extension');
  await replaceInFileRegex(
      path.path, r'^(package (?:\.|\w)+)', "package ${newPackageName}");
  String newPackagePath = newPackageName.replaceAll('.', '/');
  String newPath = '${PATH_ACTIVITY}${type}/$newPackagePath';
  print('Creating New Directory Structure');
  await Directory(newPath).create(recursive: true);
  await path.rename(newPath + '/MainActivity.$extension');
  print('Deleting old directories');
  await deleteEmptyDirs(type);
}