include timestamps in the suggested log format (#2304)

guide/src/import_hook.md

@@ -152,7 +152,7 @@ information from maturin.
 
 ```python
 import logging
-logging.basicConfig(format='%(name)s [%(levelname)s] %(message)s', level=logging.DEBUG)
+logging.basicConfig(format='%(asctime)s %(name)s [%(levelname)s] %(message)s', level=logging.DEBUG)
 import maturin_import_hook
 maturin_import_hook.reset_logger()
 maturin_import_hook.install()