Removed unused InvalidArgumentError from __main__.py.
Removed unused InvalidArgumentError from __main__.py.

This was a leftover from the old --target argparse type handler.

mesheven/pyOCD,flit/pyOCD,mbedmicro/pyOCD,mesheven/pyOCD,mbedmicro/pyOCD,pyocd/pyOCD,pyocd/pyOCD,flit/pyOCD,mesheven/pyOCD,mbedmicro/pyOCD