Syntax error when transpiling babel code

[as-cii]

In the process of upgrading babel in Atom core (atom/atom#13823) we have noticed this package doesn't transpile correctly. In particular, we have found the following errors:

• build-gulp/lib/gulp.js: Unexpected token, expected ; (38:7)

To ensure your package keeps working after we will merge and release the aforementioned pull request, please make sure to fix these errors and publish a new version.

Please, let me know if you have any questions or concerns and if I can help somehow. Thanks!