Fix external tests.

Author: ioquatix

config/external.yaml

@@ -12,7 +12,7 @@ protocol-websocket:
   command: bundle exec sus
 async-websocket:
   url: https://github.com/socketry/async-websocket.git
-  command: bundle exec rspec
+  command: bundle exec sus
 falcon:
   url: https://github.com/socketry/falcon.git
   command: bundle exec rspec