upgrade prettier to 0.16

[aaronshaf]

No description provided.

[sheerun]

I'd rather relax prettier version to <1.0.0 so we don't need to update it anymore

[dtinth]

The problem is that updating the standard and prettier inside prettier-standard-formatter requires reinstallation of the package.

I suggest one of the possible workaround, is to push standard and prettier into a peerDependency. This means the user must install standard and prettier as well, but at least they can update the version as they wish. However, I think this kinda misses the purpose of this package.