Optimize the link address

Use https instead of http to ensure the safety

Change-Id: I4b8be0de1331450753508517558acdcca66e94c5
diff --git a/HACKING.rst b/HACKING.rst
index 178e538..5281b53 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -1,7 +1,7 @@
 Patrole Style Commandments
 ==========================
 
-- Step 1: Read the OpenStack Style Commandments: `<http://docs.openstack.org/developer/hacking/>`__
+- Step 1: Read the OpenStack Style Commandments: `<https://docs.openstack.org/developer/hacking/>`__
 - Step 2: Review Tempest's Style Commandments: `<https://docs.openstack.org/developer/tempest/HACKING.html>`__
 - Step 3: Read on