pythonPackages.jaraco_itertools: fix build

The package currently fails because of some flake8 violations. However
invalid coding style shouldn't break the Nix package.

See also https://hydra.nixos.org/build/90115508
Addresses #56826

pkgs/development/python-modules/jaraco_itertools/0001-Don-t-run-flake8-checks-during-the-build.patch

@@ -0,0 +1,38 @@
+From fcffcc61e432e5250e7fbfb1ecbe0f1cac3006cf Mon Sep 17 00:00:00 2001
+From: Maximilian Bosch <maximilian@mbosch.me>
+Date: Sun, 10 Mar 2019 13:10:18 +0100
+Subject: [PATCH] Don't run flake8 checks during the build
+
+If the code simply violates their code style, the Nix package shouldn't fail.
+---
+ pytest.ini | 2 +-
+ setup.cfg  | 1 -
+ 2 files changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/pytest.ini b/pytest.ini
+index d165e5e..d8e4694 100644
+--- a/pytest.ini
++++ b/pytest.ini
+@@ -1,6 +1,6 @@
+ [pytest]
+ norecursedirs=dist build .tox .eggs
+-addopts=--doctest-modules --flake8
++addopts=--doctest-modules
+ doctest_optionflags=ALLOW_UNICODE ELLIPSIS ALLOW_BYTES
+ filterwarnings=
+ 	ignore:Possible nested set::pycodestyle:113
+diff --git a/setup.cfg b/setup.cfg
+index 9f3517f..c9033ec 100644
+--- a/setup.cfg
++++ b/setup.cfg
+@@ -30,7 +30,6 @@ setup_requires = setuptools_scm >= 1.15.0
+ testing = 
+ 	pytest >= 3.5, !=3.7.3
+ 	pytest-checkdocs
+-	pytest-flake8
+ docs = 
+ 	sphinx
+ 	jaraco.packaging >= 3.2
+-- 
+2.18.1
+

pkgs/development/python-modules/jaraco_itertools/default.nix

@@ -1,5 +1,6 @@
 { lib, buildPythonPackage, fetchPypi, setuptools_scm
-, inflect, more-itertools, six, pytest, pytest-flake8 }:
+, inflect, more-itertools, six, pytest
+}:
 
 buildPythonPackage rec {
   pname = "jaraco.itertools";
@@ -10,9 +11,11 @@ buildPythonPackage rec {
     sha256 = "d1380ed961c9a4724f0bcca85d2bffebaa2507adfde535d5ee717441c9105fae";
   };
 
+  patches = [ ./0001-Don-t-run-flake8-checks-during-the-build.patch ];
+
   buildInputs = [ setuptools_scm ];
   propagatedBuildInputs = [ inflect more-itertools six ];
-  checkInputs = [ pytest pytest-flake8 ];
+  checkInputs = [ pytest ];
 
   checkPhase = ''
     pytest