Fix for bug in pyqtdeploy:specification.py

[Patrick Stinson]

pyqtdeploy-sysroot triggers a python bug on some python installs. It is a simple workaround in pyqtdeploy/sysroot/specification.py:

from importlib import util as importlib_util

...should be used instead of...

Import importlib; importlib.util

I used pyenv to install python-3.7.8 then installed pyqtdeploy using pip. The bug did not occur when using a host python-3.7.8 built myself from source.

Cheers,
-Patrick