Change default Trino testing image to be latest

CI still has a matrix to test each PR and commit pushed to master
against both 351 and latest.

Author: hashhar

tests/integration/conftest.py

@@ -28,7 +28,7 @@
 logger = trino.logging.get_logger(__name__)
 
 
-TRINO_VERSION = os.environ.get("TRINO_VERSION") or "351"
+TRINO_VERSION = os.environ.get("TRINO_VERSION") or "latest"
 TRINO_HOST = "127.0.0.1"
 TRINO_PORT = 8080