Bump yoast/phpunit-polyfills from 2.0.1 to 3.0.0

Bumps [yoast/phpunit-polyfills](https://github.com/Yoast/PHPUnit-Polyfills) from 2.0.1 to 3.0.0.
- [Release notes](https://github.com/Yoast/PHPUnit-Polyfills/releases)
- [Changelog](https://github.com/Yoast/PHPUnit-Polyfills/blob/3.x/CHANGELOG.md)
- [Commits](Yoast/PHPUnit-Polyfills@2.0.1...3.0.0)

---
updated-dependencies:
- dependency-name: yoast/phpunit-polyfills
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -15,7 +15,7 @@
     "pantheon-systems/pantheon-wp-coding-standards": "^2.0",
     "pantheon-systems/pantheon-wordpress-upstream-tests": "dev-master",
     "phpunit/phpunit": "^9",
-    "yoast/phpunit-polyfills": "^2.0",
+    "yoast/phpunit-polyfills": "^3.0",
     "pantheon-systems/wpunit-helpers": "^2.0"
   },
   "scripts": {