Add react 18 as valid peer dependecy

[errnesto]

This simply adds react18 and react-dom18 as valid peer dependcies so this can be used with a current react version

[platramos]

Merging this in would be great because enabling peer-dependencies is a hacky solution and an anti-pattern. Thanks for making the changes @errnesto

[vandijkstef]

+1, please merge and send it! 🥳

[katistix]

+1, would really need this! Merge and release please!

[davidnoelopez]

+1, it would be great!

[BenPreston]

Yes please merge 🙏

[neilor]

When you're waiting for this, I published a package called @whats-tools/react-qr-reader which unlocks react v18 at peer dependencies. => v3.0.0-alpha.3

I've tested for a while in one particular react v18 project using npm i --force. But the best way I passed through it without adding any problems with another packages vulnerabilities was publishing this new project.