src/sage/parallel/map_reduce.py: logger.warn -> logger.warning

Fixes a DeprecationWarning:

  DeprecationWarning: The 'warn' method is deprecated, use 'warning' instead
    logger.warn(f"Profiling in {output} ...")

Author: orlitzky

src/sage/parallel/map_reduce.py

@@ -1713,7 +1713,7 @@ def run(self):
             PROFILER.runcall(self.run_myself)
 
             output = profile + str(self._iproc)
-            logger.warn(f"Profiling in {output} ...")
+            logger.warning(f"Profiling in {output} ...")
             PROFILER.dump_stats(output)
         else:
             self.run_myself()