Update wp-coding-standards/wpcs requirement from ^2.3 to ^3.1

Updates the requirements on [wp-coding-standards/wpcs](https://github.com/WordPress/WordPress-Coding-Standards) to permit the latest version.
- [Release notes](https://github.com/WordPress/WordPress-Coding-Standards/releases)
- [Changelog](https://github.com/WordPress/WordPress-Coding-Standards/blob/develop/CHANGELOG.md)
- [Commits](WordPress/WordPress-Coding-Standards@2.3.0...3.1.0)

---
updated-dependencies:
- dependency-name: wp-coding-standards/wpcs
  dependency-version: 3.1.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

composer.json

@@ -16,7 +16,7 @@
   "require-dev": {
     "phpunit/phpunit": "^9.5",
     "yoast/phpunit-polyfills": "^2.0",
-    "wp-coding-standards/wpcs": "^2.3",
+    "wp-coding-standards/wpcs": "^3.1",
     "dealerdirect/phpcodesniffer-composer-installer": "^0.7.1"
   },
   "config": {