Support React 18

[AbhiPrasad]

Problem Statement

https://reactjs.org/blog/2022/03/29/react-v18.html

Solution Brainstorm

• Update peerDependencies in @sentry/react
• Update tests to test against React 18

[AbhiPrasad]

Released as part of latest SDK version https://github.com/getsentry/sentry-javascript/releases/tag/6.19.4