Bump Python 3.10 in the CI

[Kludex]

No description provided.

[tomchristie]

So.... we really can't do anything until we've resolved this 3.9 nonsense.
Next step - figure out our workaround for that.

[Kludex]

The issue seems like the server doesn't start in the tests (running with --full-trace).

    @pytest.fixture(scope="session")
    def server():
        config = Config(app=app, lifespan="off", loop="asyncio")
        server = TestServer(config=config)
>       yield from serve_in_thread(server)

tests/conftest.py:288: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

server = <tests.conftest.TestServer object at 0x7faee6915b20>

    def serve_in_thread(server: Server):
        thread = threading.Thread(target=server.run)
        thread.start()
        try:
            while not server.started:
>               time.sleep(1e-3)
E               KeyboardInterrupt

tests/conftest.py:277: KeyboardInterrupt

I don't see what could have caused this: https://www.python.org/downloads/release/python-397/

EDIT: Running ./scripts/test tests/test_api.py gives us a hint.

[tomchristie]

Aight, sorted. 👍