DeprecationWarning on Python 3.10

[nikitagashkov]

Hi! I've encountered a deprecation warning running on Python 3.10 complaining about using distutils:

../../../.pyenv/versions/3.10.1/envs/project/lib/python3.10/site-packages/openapi_core/unmarshalling/schemas/util.py:5
  /Users/gashkov/.pyenv/versions/3.10.1/envs/project/lib/python3.10/site-packages/openapi_core/unmarshalling/schemas/util.py:5: DeprecationWarning: The distutils package is deprecated and slated for removal in Python 3.12. Use setuptools or check PEP 632 for potential alternatives
    from distutils.util import strtobool

Also, looks like there's a couple related to a new jsonschema:

  /Users/gashkov/.pyenv/versions/3.10.1/envs/project/lib/python3.10/site-packages/openapi_core/unmarshalling/schemas/unmarshallers.py:61: DeprecationWarning: Passing a schema to Validator.iter_errors is deprecated and will be removed in a future release. Call validator.evolve(schema=new_schema).iter_errors(...) instead.
    errors = tuple(errors_iter)

  /Users/gashkov/.pyenv/versions/3.10.1/envs/project/lib/python3.10/site-packages/jsonschema/validators.py:245: DeprecationWarning: Passing a schema to Validator.iter_errors is deprecated and will be removed in a future release. Call validator.evolve(schema=new_schema).iter_errors(...) instead.
    for error in self.evolve(schema=schema).iter_errors(instance):

  /Users/gashkov/.pyenv/versions/3.10.1/envs/project/lib/python3.10/site-packages/jsonschema/validators.py:276: DeprecationWarning: Passing a schema to Validator.iter_errors is deprecated and will be removed in a future release. Call validator.evolve(schema=new_schema).iter_errors(...) instead.
    error = next(self.iter_errors(instance), None)

[p1c2u]

Fixed hence closing