Upgrade to PHPCS 3.10.1

[gudmdharalds]

Upgrades PHPCS to version 3.10.1.

TODO:

• [x] Update PHPCS.
• [N/A] Add/update tests -- unit/integrated/E2E (if needed)
  • [N/A] Ensure only one function/functionality is tested per test file.
• [N/A] New/updated software requirements?
  • [N/A] Update README.md
  • [N/A] Update defines.php
• [N/A] Add to, or update, Scan run detail report as applicable
• [x] Check status of automated tests
• [N/A] Ensure PHPDoc comments are up to date for functions added or altered
• [x] Assign appropriate priority and type of change labels.
• [x] Changelog entry (for VIP) [#390]