chore(deps): update dependency php-stubs/wordpress-stubs to v5.6.0

Author: renovate-bot

composer.json

@@ -16,7 +16,7 @@
     "wp-coding-standards/wpcs": "2.3.0",
     "slevomat/coding-standard": "6.3.9",
     "edgedesign/phpqa": "1.23.3",
-    "php-stubs/wordpress-stubs": "5.4.2",
+    "php-stubs/wordpress-stubs": "5.6.0",
     "szepeviktor/phpstan-wordpress": "0.6.0",
     "nette/neon": "3.1.2",
     "vimeo/psalm": "3.11.6"