Test-requirements.txt: Bump Hacking to 0.12

We already pass all the checks.

Change-Id: I9af2eb26dfb1ecf296753dcfc505768d534929ea

Author: Jordan Pittier

test-requirements.txt

@@ -1,7 +1,7 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-hacking<0.11,>=0.10.0
+hacking>=0.12.0,!=0.13.0,<0.14  # Apache-2.0
 
 coverage>=4.0 # Apache-2.0
 fixtures>=3.0.0 # Apache-2.0/BSD