Fix python3.11 build: remove deprecated, update traceback regex

https://docs.python.org/3.11/whatsnew/3.11.html#enhanced-error-locations-in-tracebacks
Tracebacks were updated with `^^^^^..` locators surrounded by optional
`~~~..` so add an optional line that matches them into the traceback regex.

Removes unused variable and deprecated `assertRegexpMatches`.

scripts/update_releasenotes.py

@@ -724,7 +724,7 @@ def _assert_prints(self, regex, stream):
  """
  with tests.mock.patch(stream, io.BytesIO()) as mock:
  yield
- self.assertRegexpMatches(mock.getvalue(), regex)
+ self.assertRegex(mock.getvalue(), regex)
 
  def _assert_iter_equal(self, actual, expected):
  """Test whether two iterables are equal.

tests/support.py

@@ -77,7 +77,8 @@ def mock_open(mock=None, data=None):
 TRACEBACK_RE = re.compile(
  r'(Traceback \(most recent call last\):\n'
  r'(?: File "[^"\n]+", line \d+, in \w+\n'
- r'(?: .+\n)?)+'
+ r'(?: .+\n)?'
+ r'(?: \s*\~*\^+\~*\n)?)+'
  r'\S.*\n)')
 REASONS = {
  'hole': 'group',
@@ -585,7 +586,6 @@ class TestCase(unittest.TestCase):
 
  if not dnf.pycomp.PY3:
  assertCountEqual = unittest.TestCase.assertItemsEqual
- assertRegex = unittest.TestCase.assertRegexpMatches
 
  def assertEmpty(self, collection):
  return self.assertEqual(len(collection), 0)