convert shebang lines: python -> python3
diff --git a/Tools/scripts/pysource.py b/Tools/scripts/pysource.py
index 05c2b86..048131e 100644
--- a/Tools/scripts/pysource.py
+++ b/Tools/scripts/pysource.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """\
 List python source files.