MVP support for React 19

[stefcameron]

focus-trap-react was already "ready" for React 19. All that was necessary was to drop prop-types, which has been removed as a dependency.

It's also time to move forward and stop supporting ancient versions of React. Therefore, the minimum supported version of React will now be 18.0.0, and I intend for that remain one version behind the latest version going forward, provided the gap between the two is reasonably surmountable.

PR Checklist

Please leave this checklist in your PR.

• Issue being fixed is referenced.
• Source changes maintain:
  • Stated browser compatibility.
  • Stated React compatibility.
• Web APIs introduced have deep browser coverage, including Safari (often very late to adopt new APIs).
• Unit test coverage added/updated.
• E2E test coverage added/updated.
• Prop-types added/updated.
• Typings added/updated.
• Changes do not break SSR:
  • Careful to test typeof document/window !== 'undefined' before using it in code that gets executed on load.
• README updated (API changes, instructions, etc.).
• Changes to dependencies explained.
• Changeset added (run npm run changeset locally to add one, and follow the prompts).
  • EXCEPTION: A Changeset is not required if the change does not affect any of the source files that produce the package bundle. For example, demo changes, tooling changes, test updates, or a new dev-only dependency to run tests more efficiently should not have a Changeset since it will not affect package consumers.

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: f7062077e5a87be654213b49209c4dea99397e32

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
focus-trap-react	Major

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[stefcameron]

React 19 is live: https://react.dev/blog/2024/12/05/react-19