Composer: require YoastCS ^1.2.2

[jrfnl]

Summary

This PR can be summarized in the following changelog entry:

• N/A

Relevant technical choices:

Updates the CS requirements to YoastCS 1.2.2, including updating the dependencies.

No changes to the code are needed.

The selective exclusion for namespaced files without file comment can now be removed as YoastCS 1.2.0+ has a sniff which takes that into account.

Refs:

• https://github.com/Yoast/yoastcs/releases/tag/1.2.0
• https://github.com/Yoast/yoastcs/releases/tag/1.2.1
• https://github.com/Yoast/yoastcs/releases/tag/1.2.2

Test instructions

This PR can be tested by following these steps:

• Either do a composer install and then a vendor/bin/phpcs òr check the Travis logs for the CS run to verify that all is well.