addFlagGenerateL10n method
Adds a generate l10n flag for localization generation.
Generate l10n first before running other command.
Defaults to true.
Example:
argParser.addFlagGenerateL10n(defaultsTo: false);
Implementation
void addFlagGenerateL10n({bool defaultsTo = true}) {
  addFlag(
    'l10n',
    help: 'Generate l10n first before running other command.',
    defaultsTo: defaultsTo,
  );
}