add phpunit dependency

Author: simonLeary42

Diff for: composer.json

@@ -4,5 +4,8 @@
         "phpseclib/phpseclib": "3.0.43",
         "phpmailer/phpmailer": "6.6.4",
         "hakasapl/phpopenldaper": "1.0.5"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^12.1"
     }
 }