convert shebang lines: python -> python3
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index 9f631f4..d4f40aa 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 """Regression test.