add supported phpunit versions

Author: ddrv

composer.json

@@ -16,7 +16,7 @@
         "ext-mbstring": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8.35 || ^5.7",
+        "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.5 || ^7.5 || ^8.5 || 9.3",
         "squizlabs/php_codesniffer": "^3.5"
     },
     "suggest": {

phpunit.xml.dist

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="vendor/autoload.php" colors="true">
+<phpunit bootstrap="vendor/autoload.php" colors="true" cacheResult="false">
     <testsuites>
         <testsuite name="all">
             <directory>tests</directory>