test: change wait_for_readiness to an enum

This so we can wait for both readiness and liveness

test/io/test_auth.py

@@ -167,7 +167,7 @@ def test_fail_with_invalid_password(defaultenv):
     "Connecting with an invalid password should fail without retries."
     uri = f'postgresql://?dbname={defaultenv["PGDATABASE"]}&host={defaultenv["PGHOST"]}&user=some_protected_user&password=invalid_pass'
     env = {**defaultenv, "PGRST_DB_URI": uri}
-    with run(env=env, wait_for_readiness=False) as postgrest:
+    with run(env=env, wait_for=None) as postgrest:
         exitCode = wait_until_exit(postgrest)
         assert exitCode == 1