Add wheel option, universal

Signed-off-by: Deokgyu Yang <secugyu@gmail.com>
diff --git a/setup.cfg b/setup.cfg
index 0167558..e7291c5 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -5,3 +5,6 @@
 description= A Port of WiringPi Python project for ODROID boards
 long_description = file:README.rst
 license = LGPL
+
+[bdist_wheel]
+universal = 1