Allow Symfony Process 5.0 (#152)

Author: samail

composer.json

@@ -33,7 +33,7 @@
     },
     "require": {
         "php": "^5.6 || ^7.0",
-        "symfony/process": "^3.4|^4.0"
+        "symfony/process": "^3.4|^4.0|^5.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^5.7|^6.5|^7.0",