Bump yoast/phpunit-polyfills from 3.1.1 to 4.0.0

Bumps [yoast/phpunit-polyfills](https://github.com/Yoast/PHPUnit-Polyfills) from 3.1.1 to 4.0.0.
- [Release notes](https://github.com/Yoast/PHPUnit-Polyfills/releases)
- [Changelog](https://github.com/Yoast/PHPUnit-Polyfills/blob/4.x/CHANGELOG.md)
- [Commits](Yoast/PHPUnit-Polyfills@3.1.1...4.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

composer.json

@@ -30,7 +30,7 @@
     "szepeviktor/phpstan-wordpress": "^1.3",
     "wp-coding-standards/wpcs": "^3.1",
     "wp-phpunit/wp-phpunit": "^6.5",
-    "yoast/phpunit-polyfills": "^3.1",
+    "yoast/phpunit-polyfills": "^4.0",
     "phpstan/php-8-stubs": "^0.4.0",
     "phpstan/phpstan-strict-rules": "^1.6"
   },