lite: pyodide 0.20.x support

[datakurre]

Robot tests / tasks with errors fail with pyodide 0.20.0.

Maybe just wait for the next pyodide release.

PythonError: Traceback (most recent call last):
  File "/lib/python3.10/site-packages/robotkernel/display_pyolite.py", line 115, in run
    return self.do_execute(code, silent=False)
  File "/lib/python3.10/site-packages/robotkernel/kernel.py", line 269, in do_execute
    result = execute_robot(
  File "/lib/python3.10/site-packages/robotkernel/executors.py", line 222, in execute_robot
    reply = run_robot_suite(
  File "/lib/python3.10/site-packages/robotkernel/executors.py", line 268, in run_robot_suite
    results = suite.run(outputdir=path, stdout=stdout, listener=listeners)
  File "/lib/python3.10/site-packages/robot/running/model.py", line 402, in run
    with STOP_SIGNAL_MONITOR:
  File "/lib/python3.10/site-packages/robot/running/signalhandler.py", line 50, in __enter__
    self._register_signal_handler(signum)
  File "/lib/python3.10/site-packages/robot/running/signalhandler.py", line 64, in _register_signal_handler
    signal.signal(signum, self)
  File "/lib/python3.10/signal.py", line 56, in signal
    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
OSError: [Errno 0] Error

[bollwyvl]

Little update: we're getting close to a jupyterlite release with pyodide 0.21.2 and lab 3.4.7, and better support for #99. Hopefully this week... and, of note: the kernel filesystem and server/browser contents now basically unified, which means it would be possible to import and Library relative paths that are deployed with the application, or written on the fly.

Probably worth taking another look when that release lands.