convert shebang lines: python -> python3
diff --git a/Demo/cgi/cgi3.py b/Demo/cgi/cgi3.py
index a3421b5..de8ef65 100755
--- a/Demo/cgi/cgi3.py
+++ b/Demo/cgi/cgi3.py
@@ -1,4 +1,4 @@
-#!/usr/local/bin/python
+#!/usr/bin/env python3
 
 """CGI test 3 (persistent data)."""