Docs: update for 10.0.0 release, remove .devcontainer
Bump version for 10.0.0 release.
Also:
- Remove the
.devcontainerfolder, since the Docker image there is no longer up to date, and not that useful. - Pin pytest-asyncio >= 0.24. The
asyncio_default_fixture_loop_scopeoption was added in pytest-asyncio 0.24.0. Using earlier versions will fail, due the unknown ini option.