Coding Standards: Upgrade WPCS to version 3.1.0.

The impact on existing WordPress core code is expected to be minimal, but the release does provide more safeguards for the future.

References:
* [https://github.com/WordPress/WordPress-Coding-Standards/releases/tag/3.1.0 WPCS 3.1.0 release notes]
* [WordPress/WordPress-Coding-Standards@3.0.1...3.1.0 Full list of changes in WPCS 3.1.0]

Follow-up to [56695], [56799], [57378].

Props jrf, garyj, dingo_d, rodrigosprimo, Chouby, westonruter, bjorsch.
Fixes #60840.
Built from https://develop.svn.wordpress.org/trunk@57986


git-svn-id: http://core.svn.wordpress.org/trunk@57472 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.6-alpha-57985';
+$wp_version = '6.6-alpha-57986';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.