Fix DeprecationWarning: The 'warn' method is deprec.

Launcher tests showed a warning about warnings that should use 'warning'
instead of 'warn()'

(test on: openqa)

Author: deeplow

sdw_updater/Updater.py

@@ -204,7 +204,7 @@ def _qubes_updater_parse_progress(stream, result, templates, progress_callback=N
         try:
             vm, status, info = line.split()
         except ValueError:
-            sdlog.warn("Line in Qubes updater's output could not be parsed")
+            sdlog.warning("Line in Qubes updater's output could not be parsed")
             continue
 
         if status == "updating":