Update .gitignore to not ignore auth.json lan file. (laravel#6515)

Author: Tjoosten

.gitignore

@@ -13,9 +13,9 @@
 .phpunit.result.cache
 Homestead.json
 Homestead.yaml
-auth.json
 npm-debug.log
 yarn-error.log
+/auth.json
 /.fleet
 /.idea
 /.nova