Added Symfony var dumper to dev dependencies

Author: caseyamcl

composer.json

@@ -31,7 +31,8 @@
         "phpstan/extension-installer": "^1.0",
         "phpstan/phpstan": "^1.0",
         "phpunit/phpunit": "^7.5|^8.0|^9.0",
-        "squizlabs/php_codesniffer": "^3.5"
+        "squizlabs/php_codesniffer": "^3.5",
+        "symfony/var-dumper": "^5.0|^6.0|^7.0"
     },
     "autoload": {
         "psr-4": {