Update satooshi/php-coveralls requirement from ^1.0 to ^2.0

Updates the requirements on [satooshi/php-coveralls](https://github.com/php-coveralls/php-coveralls) to permit the latest version.
- [Release notes](https://github.com/php-coveralls/php-coveralls/releases)
- [Changelog](https://github.com/php-coveralls/php-coveralls/blob/2.1/CHANGELOG.md)
- [Commits](https://github.com/php-coveralls/php-coveralls/commits/v2.0.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

composer.json

@@ -15,7 +15,7 @@
     "codeception/codeception": ">=2.2"
   },
   "require-dev": {
-    "satooshi/php-coveralls": "^1.0"
+    "satooshi/php-coveralls": "^2.0"
   },
   "autoload": {
     "psr-4": {