doc: add version info

[yufansong]

Some syntax in our code require python >= 3.10 for example:

    def __init__(
        self,
        workspace_dir: str | None = None,
        container_image: str | None = None,
        timeout: int = 120,
        id: str | None = None
    ):

the python 3.9 cannot recognize str | None = None