Remove dependencies not needed to run tests.

--- stestr-4.1.0/test-requirements.txt.orig
+++ stestr-4.1.0/test-requirements.txt
@@ -2,10 +2,8 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking<3.2.0,>=3.1.0
 sphinx>2.1.0 # BSD
 coverage>=4.0 # Apache-2.0
 ddt>=1.0.1 # MIT
 iso8601 # MIT
-doc8>=0.8.0 # Apache-2.0
 black~=22.0