README: change code.google.com link to GitHub

Signed-off-by: David Symonds <dsymonds@golang.org>

README

diff --git a/README b/README
index 5f9c114..387b4eb 100644
--- a/README
+++ b/README
@@ -5,7 +5,7 @@
 
 This is an efficient pure Go implementation of leveled logs in the
 manner of the open source C++ package
-	http://code.google.com/p/google-glog
+	https://github.com/google/glog
 
 By binding methods to booleans it is possible to use the log package
 without paying the expense of evaluating the arguments to the log.