Update hacking

Update hacking to latest version to catch Python 3 problems.

The existing entries in flake8 ignore are dropped
as they are unnecessary.

Change-Id: I8e268f3852ad7acf4805f8ef7e4cbe25a90054a0
diff --git a/test-requirements.txt b/test-requirements.txt
index 702a3af..b986009 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<0.11,>=0.10.0
+hacking>=2.0,<2.1 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
 oslosphinx>=4.7.0 # Apache-2.0