Bump to 4.18.0

[compulim]

Related to #5239.

Changelog Entry

(Marking unreleased entries as 4.18.0)

Description

Preparing to release 4.18.0.

Specific Changes

• Update README.md with notable changes
• Update CHANGELOG.md to mark entries as 4.18.0
• npm version --no-git-tag-version 4.18.0

• [x] ~I have added tests and executed them locally~
• [x] I have updated CHANGELOG.md
• [x] I have updated documentation

Review Checklist

This section is for contributors to review your work.

• [x] ~Accessibility reviewed (tab order, content readability, alt text, color contrast)~
• [x] Browser and platform compatibilities reviewed
• [x] ~CSS styles reviewed (minimal rules, no z-index)~
• [x] ~Documents reviewed (docs, samples, live demo)~
• [x] ~Internationalization reviewed (strings, unit formatting)~
• [x] package.json and package-lock.json reviewed
• [x] ~Security reviewed (no data URIs, check for nonce leak)~
• [x] ~Tests reviewed (coverage, legitimacy)~

[compulim]

Flaky test.