Upgrade peerDep range to include React 17

[emplums]

Let's make the library usable with React 17 by updating the peerDeps range. Ideally we can allow either ^16.8 and ^17.

Another project at GitHub using PRC is running into issues with the event delegation in older versions and is reliant on PRC upgrading to version 17 to move forward with shipping bug fixes.

[emplums]

Update: I think we should limit usage to just v17 and up. Because v17 includes changes to how event delegation works, it seems risky to allow either React 16 or React 17.

[emplums]

This has been merged into the major release branch