[BUG] Not compatible with Python<3.9

[sighingnow]

Describe the bug

cancel_futures was added since Python 3.9.

Error: -27 16:48:33,599 [ERROR][rpc:222]: Runstep failed with code: INTERACTIVE_ENGINE_INTERNAL_ERROR, message: Error occurred during preprocessing, The traceback is: Traceback (most recent call last):
  File "/Users/runner/.local/lib/python3.8/site-packages/gscoordinator/coordinator.py", line 696, in _create_interactive_instance
    if check_gremlin_server_ready(maxgraph_endpoint):
  File "/Users/runner/.local/lib/python3.8/site-packages/gscoordinator/utils.py", line 1779, in check_gremlin_server_ready
    executor.shutdown(wait=False, cancel_futures=True)
TypeError: shutdown() got an unexpected keyword argument 'cancel_futures'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/runner/.local/lib/python3.8/site-packages/gscoordinator/coordinator.py", line 516, in RunStep
    self.run_on_interactive_engine(
  File "/Users/runner/.local/lib/python3.8/site-packages/gscoordinator/coordinator.py", line 433, in run_on_interactive_engine
    op_result = self._create_interactive_instance(op)
  File "/Users/runner/.local/lib/python3.8/site-packages/gscoordinator/coordinator.py", line 722, in _create_interactive_instance
    raise RuntimeError("Create interactive instance failed.") from e
RuntimeError: Create interactive instance failed.

See also: https://github.com/alibaba/GraphScope/runs/4967615199?check_suite_focus=true, and https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.Executor.shutdown