Update utils.py for py3.9+ compatibility

[yuenherny]

Running the evaluation with Python 3.10.5 results in:
ValueError: Function has keyword-only parameters or annotations, use inspect.signature() API which can support them

Hence. replacing the legacy inspect.getargspec method with inspect.getfullargspec method, as per here:

# check that we give good parameters to the optimizer
    expected_args = inspect.getfullargspec(optim_fn.__init__)
    assert expected_args.args[:2] == ['self', 'params']
    if not all(k in expected_args.args[2:] for k in optim_params.keys()):
        raise Exception('Unexpected parameters: expected "%s", got "%s"' % (
            str(expected_args.args[2:]), str(optim_params.keys())))

This commit fixes this issue: facebookresearch#88. This fix was originated from this PR facebookresearch#87 which did not get merged after such a long time. Hence I forked this repo and implemented this fix myself.

Tested on Windows with Python 3.10.5.