convert shebang lines: python -> python3
diff --git a/Tools/scripts/serve.py b/Tools/scripts/serve.py
index 61de63d..e4074c1 100755
--- a/Tools/scripts/serve.py
+++ b/Tools/scripts/serve.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 '''
 Small wsgiref based web server. Takes a path to serve from and an
 optional port number (defaults to 8000), then tries to serve files.