Bump CI/CD versions to PHP 8.3, WP 6.5 and tested up to 6.6

[EvanHerman]

• Bump tested up to value to WordPress 6.6
• Update the bage in README.md
• Update CI/CD pipeline to use WordPress 6.5
• Update CI/C pipeline with new PHP 8.3 tests
• Fix CI/CD pipelines so they are running and passing again
  • Update .nvrmc to 18
  • Update yoast/polyfills to 1.1.0
  • Set a resolution in package.json for "eslint-plugin-jsdoc": "^41.0.0"
  • Update command to run PHP unit
  • Remove the Prepare tests step, since it is no longer needed.
  • Update package.json dependencies