Use https:// for all project links where available (#267)

diff --git a/examples/rewrite_ast.py b/examples/rewrite_ast.py
index eae6539..2c42f99 100644
--- a/examples/rewrite_ast.py
+++ b/examples/rewrite_ast.py
@@ -3,7 +3,7 @@
 #
 # Tiny example of rewriting a AST node
 #
-# Eli Bendersky [http://eli.thegreenplace.net]
+# Eli Bendersky [https://eli.thegreenplace.net/]
 # License: BSD
 #-----------------------------------------------------------------
 from __future__ import print_function