Update Psalm to 6.8.8

Author: BenMorel

composer.json

@@ -24,7 +24,7 @@
     "require-dev": {
         "phpunit/phpunit": "^10.1",
         "php-coveralls/php-coveralls": "^2.2",
-        "vimeo/psalm": "6.3.0"
+        "vimeo/psalm": "6.8.8"
     },
     "autoload": {
         "psr-4": {