Merge pull request #115 from Thiago-Medeiros/fix-phpunit-version

fix: downgrade phpunit min version

Author: s2it-moscou

composer.json

@@ -14,7 +14,7 @@
     "lib-openssl": "*"
   },
   "require-dev": {
-    "phpunit/phpunit": "^5.7"
+    "phpunit/phpunit": "^4.8"
   },
   "autoload": {
     "psr-4": {