Uncap test requirements

Newer stestr is needed to avoid failures on Python 3.11 like:

    nox > stestr run --color
    stestr: 'run --color' is not a stestr command.

Go ahead and uncap all the test dependencies. Also drop the pbr
addition for Python<=3.5 since we no longer test with anything older
than 3.6 anyway, and fix an exception that hacking seems to really
not want us to use.

Change-Id: I85585324c4e47d37b6de555110066fb8c29f293f

git_review/tests/test_unit.py

@@ -105,7 +105,7 @@ class GitReviewConsole(testtools.TestCase, fixtures.TestWithFixtures):
 
         try:
             with mock.patch('sys.argv', ['git-review', '--version']):
-                with self.assertRaisesRegexp(SystemExit, '1'):
+                with self.assertRaisesRegex(SystemExit, '1'):
                     cmd.main()
         except Exception as e:
             self.fail('Exception not expected: %s' % e)

test-requirements.txt

@@ -1,8 +1,4 @@
-# This is listed in order to preinstall PBR with pip as easy_install
-# on these older python versions can no longer reliably talk to pypi
-# due to non SNI TLS connections being disabled.
-pbr ; python_version >= "3" and python_version <= "3.5"
-hacking>=2.0.0,<2.1.0
+hacking>=2.0.0
 fixtures>=0.3.14
-stestr>=2.2.0,<3.0.0
+stestr>=2.2.0
 testtools>=0.9.34