convert shebang lines: python -> python3
diff --git a/Demo/curses/life.py b/Demo/curses/life.py
index ddff8fa..06f9692 100755
--- a/Demo/curses/life.py
+++ b/Demo/curses/life.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # life.py -- A curses-based version of Conway's Game of Life.
 # Contributed by AMK
 #