Add symfony thanks

ssfinney · ssfinney · commit 11c1fbb4c882 · 2018-03-16T11:21:57.000-04:00
diff --git a/composer.json b/composer.json
@@ -25,6 +25,7 @@
         "phpunit/phpunit": "~4.0|~5.0|~6.0|~7.0",
         "psy/psysh": "^0.5.1",
         "satooshi/php-coveralls": "^0.6.1|^1",
+        "symfony/thanks": "^1.0",
         "symfony/var-dumper": "~2.7|~3.0"
     },
     "autoload": {
