Upgrade phpspec coverage plugin

Author: sagikazarmark

composer.json

@@ -25,7 +25,7 @@
         "psr/http-message": "^1.0"
     },
     "require-dev": {
-        "friends-of-phpspec/phpspec-code-coverage": "^4.1",
+        "friends-of-phpspec/phpspec-code-coverage": "^4.3",
         "phpspec/phpspec": "^4.3.4 || ^5.0 || ^6.0"
     },
     "extra": {