Update composer.json

Author: DavertMik

composer.json

@@ -10,10 +10,10 @@
         }
     ],
     "require": {
-        "phpunit/phpunit": "^7.0",
-        "phpunit/php-code-coverage": "^6.0",
-        "sebastian/comparator": "^2.0",
-        "sebastian/diff": "^3.0"
+        "phpunit/phpunit": ">=4.8.28 <5.0.0 || >=5.6.3 <7.0",
+        "phpunit/php-code-coverage": ">=2.2.4 <6.0",
+        "sebastian/comparator": ">1.1 <3.0",
+        "sebastian/diff": ">=1.4 <4.0"
     },
     "autoload":{
         "psr-4":{