Composer: update minimum version PHPCSUtils

PHPCSUtils has just released version 1.2.3, which includes a security fix which is relevant for two sniffs which are included in PHPCSExtra.

With that in mind, I'm bumping the minimum supported PHPCSUtils version to encourage users of PHPCSExtra to upgrade.

Why does a version bump in PHPCSExtra help ?

Well, it only helps when a new version of PHPCSExtra is released, which is what I intend to do next.
Once that's done, it helps as Composer will now show PHPCSExtra as a direct dependency which is outdated, while PHPCSUtils would only show as an indirect dependency which is outdated, which doesn't have the same urgency for people to update.

Ref: https://github.com/PHPCSStandards/PHPCSUtils/releases/tag/1.2.3

Author: jrfnl

composer.json

@@ -29,7 +29,7 @@
     },
     "require": {
         "php": ">=5.4",
-        "phpcsstandards/phpcsutils": "^1.2.0",
+        "phpcsstandards/phpcsutils": "^1.2.3",
         "squizlabs/php_codesniffer": "^3.13.5 || ^4.0.1"
     },
     "require-dev": {