Build/Test Tools: Update PHPStan to 2.3.4.

This also brings in the 2.3.3 release, which replaces the regular expression parser used to infer the shapes of `preg_match()` and `preg_match_all()` matches, along with a number of type resolution and robustness fixes. The 2.3.4 release follows with fixes to unions involving constant scalars.

Developed in #15137.
Follow-up to r64757.

Props westonruter, lancewillett, mukesh27.
See #65817.


git-svn-id: https://develop.svn.wordpress.org/trunk@65078 602fd350-edb4-49c9-b593-d223f7449a82

Author: westonruter

composer.json

@@ -52,7 +52,7 @@
 		"squizlabs/php_codesniffer": "3.13.5",
 		"wp-coding-standards/wpcs": "~3.4.1",
 		"phpcompatibility/phpcompatibility-wp": "~2.1.3",
-		"phpstan/phpstan": "2.3.2",
+		"phpstan/phpstan": "2.3.4",
 		"phpstan/phpstan-phpunit": "2.1.1",
 		"yoast/phpunit-polyfills": "^1.1.0"
 	},