Add async-websocket to external tests.

Author: ioquatix

config/external.yaml

@@ -1,3 +1,6 @@
 falcon:
   url: https://github.com/socketry/falcon
   command: bundle exec bake test
+async-websocket:
+  url: https://github.com/socketry/async-websocket
+  command: bundle exec bake test