DeprecationWarning: There is no current event loop

[philvarner]

Running tests yields deprecation warning

tests/test_task_download.py::test_download_nosuch_asset
  /Users/philvarner/code/stac-task/stactask/task.py:238: DeprecationWarning: There is no current event loop
    loop = asyncio.get_event_loop()

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html

Description of the issue is here: https://stackoverflow.com/questions/73361664/asyncio-get-event-loop-deprecationwarning-there-is-no-current-event-loop