update driver list

config/logging.php

@@ -24,8 +24,8 @@ return [
     | the box, Laravel uses the Monolog PHP logging library. This gives
     | you a variety of powerful log handlers / formatters to utilize.
     |
-    | Available Drivers: "single", "daily", "syslog",
-    |                    "errorlog", "custom"
+    | Available Drivers: "single", "daily", "slack", "syslog",
+    |                    "errorlog", "custom", "stack"
     |
     */