Drop flake8-docstrings

This is no longer maintained [1].

[1] https://github.com/PyCQA/flake8-docstrings/issues/68

Change-Id: Ic98fc4be3612a3cfc5d3e2e85918c20ffaed873d
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

.pre-commit-hooks.yaml

@@ -5,8 +5,3 @@
   language: python
   types: [python]
   require_serial: true
-  additional_dependencies:
-    # This enables the pep257 extra from hacking by default. If you want
-    # to avoid it, just override additional_dependencies in your hook config
-    # by listing only `- .`. We assume that most users want this feature.
-    - .[pep257]

setup.cfg

@@ -62,7 +62,3 @@ flake8.extension =
     H903 = hacking.checks.other:hacking_no_cr
     H904 = hacking.checks.other:hacking_delayed_string_interpolation
     H905 = hacking.checks.imports:hacking_no_eventlet
-
-[extras]
-pep257 =
-  flake8-docstrings==1.7.0 # MIT