update hacking pin to support flake8 3.8.3

this change updates the max version of hacking
to 4.1.0 to allow pre-commit to work with the
flake 3.8.3 release and correct one new error that was
raised as a result.

Change-Id: I3a0242208f411b430db0e7429e2c773f45b3d301

.pre-commit-config.yaml

@@ -32,7 +32,7 @@ repos:
       - id: flake8
         name: flake8
         additional_dependencies:
-          - hacking>=3.0.1,<3.1.0
+          - hacking>=3.0.1,<=4.1.0
         language: python
         entry: flake8
         files: '^.*\.py$'

oslo_messaging/tests/test_transport.py

@@ -115,7 +115,7 @@ class GetTransportTestCase(test_utils.BaseTestCase):
         self.assertIsNotNone(transport_)
         self.assertIs(transport_.conf, self.conf)
         self.assertIs(transport_._driver, drvr)
-        self.assertTrue(isinstance(transport_, transport.RPCTransport))
+        self.assertIsInstance(transport_, transport.RPCTransport)
 
         driver.DriverManager.assert_called_once_with('oslo.messaging.drivers',
                                                      self.expect['backend'],

test-requirements.txt

@@ -3,7 +3,7 @@
 # process, which may cause wedges in the gate later.
 
 # Hacking already pins down pep8, pyflakes and flake8
-hacking>=3.0.1,<3.1.0 # Apache-2.0
+hacking>=3.0.1,<=4.1.0 # Apache-2.0
 
 fixtures>=3.0.0 # Apache-2.0/BSD
 stestr>=2.0.0 # Apache-2.0