updateAvailableGenerators() {
    this.generators = {};

    const resolveGenerators = generator => {
      // Skip sub generators
      if (!/:(app|all)$/.test(generator.namespace)) {
        return;
      }

      const {packageJson: package_} = readPackageUpSync({cwd: path.dirname(generator.resolved)});

      if (!package_) {
        return;
      }

      package_.namespace = generator.namespace;
      package_.appGenerator = true;
      package_.prettyName = titleize(humanizeString(namespaceToName(generator.namespace)));
      package_.update = updateNotifier({pkg: package_}).update;

      if (package_.update && package_.version !== package_.update.latest) {
        package_.updateAvailable = true;
      }

      this.generators[package_.name] = package_;
    };

    for (const generator of Object.values(this.env.getGeneratorsMeta())) {
      resolveGenerators(generator);
    }
  }
Update the available generators in the app
TODO: Move this function elsewhere, try to make it stateless.