Update php_codesniffer dependency to support PHP 7.4

[pereirinha]

Description of the Change

Update php_codesniffer dependency to support PHP 7.4

Benefits

Running the older version trows notifications and that prevents PHPCS from running properly.

Checklist:

• [ ] I have read the CONTRIBUTING document.
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my change.
• [ ] All new and existing tests passed.

[jeffpaul]

@tlovett1 any updates on your review of this PR?

[claytoncollie]

This PR is not needed anymore. #35 bumps the test version to 8.1. Closing.