deps: update peerDeps to support React 18 without warnings

[agilgur5]

Summary

Update peerDependencies range to support React 18. Update devDeps, tests, example, to support / use React 18

• Fixes #76
• Replaces / Closes #77

Details

• seems to work without any component modifications needed on React 18

  • React 18 was mostly deprecations and new features per the upgrade guide: https://reactjs.org/blog/2022/03/08/react-18-upgrade-guide.html
  • React 18 has concurrent mode opt-in, which is technically breaking, but doesn't seem to effect this library (fortunately)

• ensure tests pass with React 18

  • update devDeps to React 18, react-dom 18, @types/react 18
  • update devDeps to RTL 13 which supports React 18
  • see previous PR (#88) for the migration from Enzyme to RTL since Enzyme never had official support for React 17, let alone React 18

Next Steps

Backport this to v1.0.6, i.e. prior to the TypeScript rewrite (#42) being merged. I'll have to cherry-pick a number of commits to get that to work, but should hopefully get it working quickly.

• update example to use createRoot instead of ReactDOM.render
  • this is one of the opt-ins to React 18 mode, and doesn't seem to change anything about the example (just no warnings anymore)