pre-commit is not needed to run tests.

--- pbr-6.1.1/test-requirements.txt.orig
+++ pbr-6.1.1/test-requirements.txt
@@ -18,5 +18,3 @@
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4' # BSD
 testrepository>=0.0.18 # Apache-2.0/BSD
-
-pre-commit>=2.6.0;python_version>='3.6' # MIT