[FEATURE] Add Python 3.10 support

[Stranger6667]

We need:

• Trove classifier in the pyproject.toml file
• Builds

[Pentusha]

Seems like just changes the classifier and build steps are not enough. Traceback for tests against dependabot's PR with python 3.10.

tests_1     |   File "/env/lib/python3.10/site-packages/_pytest/assertion/rewrite.py", line 170, in exec_module
tests_1     |     exec(co, module.__dict__)
tests_1     |   File "/env/lib/python3.10/site-packages/schemathesis/fixups/fast_api.py", line 3, in <module>
tests_1     |     from ..hooks import HookContext, register, unregister
tests_1     |   File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
tests_1     |   File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
tests_1     |   File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
tests_1     |   File "/env/lib/python3.10/site-packages/_pytest/assertion/rewrite.py", line 170, in exec_module
tests_1     |     exec(co, module.__dict__)
tests_1     |   File "/env/lib/python3.10/site-packages/schemathesis/hooks.py", line 10, in <module>
tests_1     |     from .utils import GenericResponse, deprecated_property
tests_1     |   File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
tests_1     |   File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
tests_1     |   File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
tests_1     |   File "/env/lib/python3.10/site-packages/_pytest/assertion/rewrite.py", line 170, in exec_module
tests_1     |     exec(co, module.__dict__)
tests_1     |   File "/env/lib/python3.10/site-packages/schemathesis/utils.py", line 28, in <module>
tests_1     |     import requests
tests_1     |   File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
tests_1     |   File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
tests_1     |   File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
tests_1     |   File "/env/lib/python3.10/site-packages/_pytest/assertion/rewrite.py", line 170, in exec_module
tests_1     |     exec(co, module.__dict__)
tests_1     |   File "/env/lib/python3.10/site-packages/requests/__init__.py", line 133, in <module>
tests_1     |     from . import utils
tests_1     |   File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
tests_1     |   File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
tests_1     |   File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
tests_1     |   File "/env/lib/python3.10/site-packages/_pytest/assertion/rewrite.py", line 170, in exec_module
tests_1     |     exec(co, module.__dict__)
tests_1     |   File "/env/lib/python3.10/site-packages/requests/utils.py", line 41, in <module>
tests_1     |     DEFAULT_CA_BUNDLE_PATH = certs.where()
tests_1     |   File "/env/lib/python3.10/site-packages/certifi/core.py", line 37, in where
tests_1     |     _CACERT_PATH = str(_CACERT_CTX.__enter__())
tests_1     |   File "/usr/local/lib/python3.10/contextlib.py", line 135, in __enter__
tests_1     |     return next(self.gen)
tests_1     |   File "/usr/local/lib/python3.10/importlib/_common.py", line 87, in _tempfile
tests_1     |     fd, raw_path = tempfile.mkstemp(suffix=suffix)
tests_1     |   File "/usr/local/lib/python3.10/tempfile.py", line 337, in mkstemp
tests_1     |     return _mkstemp_inner(dir, prefix, suffix, flags, output_type)
tests_1     |   File "/usr/local/lib/python3.10/tempfile.py", line 249, in _mkstemp_inner
tests_1     |     file = _os.path.join(dir, pre + name + suf)
tests_1     | TypeError: can only concatenate str (not "method") to str

[Stranger6667]

@Pentusha Hi! Long time no see :)

Thank you for sharing this :) Looks like indeed we need to wait a bit for the new requests / certifi versions