Update dependency satooshi/php-coveralls to v2

Author: renovate-bot

composer.json

@@ -24,7 +24,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "~4.8",
-        "satooshi/php-coveralls": "~1.0",
+        "satooshi/php-coveralls": "~2.0",
         "squizlabs/php_codesniffer": "~2.6",
         "friendsofphp/php-cs-fixer": "~1.12"
     },