Update hacking for Python3

The repo is Python 3 now, so update hacking to version 3.0 which
supports Python 3.

Fix problems found.

Change-Id: I76d42ef91d3cfc133a6f7a4dfdf982e5fec0d443
diff --git a/test-requirements.txt b/test-requirements.txt
index 337b82e..a1ec376 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking<0.13,>=0.12.0 # Apache-2.0
+hacking>=3.0,<3.1.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
 python-subunit>=1.0.0 # Apache-2.0/BSD