add phpunit dep

Author: l0gicgate

composer.json

@@ -23,8 +23,8 @@
     "psr/http-server-middleware": "^1.0"
   },
   "require-dev": {
+    "phpunit/phpunit": "^8.5.13 || ^9.3.8",
     "slim/psr7": "^1.1",
-    "phpunit/phpunit": "^8.5",
     "squizlabs/php_codesniffer": "^3.5",
     "phpstan/phpstan": "^0.12.28"
   },