Update `purescript-react` version

[elliotdavies]

Hello! purescript-react just released v8.0.0, which includes updates to the React refs API. I'd like to upgrade the package-set to include this new version but Concur will have to put out an updated release first since it's also in the set 😄

As far as I can tell this should just be a case of updating the ref prop type here.

[ajnsit]

I have pushed tag v0.3.9 which uses purescript-react-8.0. Is that all that's needed?

[elliotdavies]

@ajnsit Yep that's all! Thanks a bunch.