Add missing packaging module, fixes the following backtrace while trying
to use labgrid-client:
Traceback (most recent call last):
File "/nix/store/izj1dw63bqh47bq10v1b2d7qqg9al7f7-python3.9-labgrid-0.4.1/bin/.labgrid-client-wrapped", line 6, in <module>
from labgrid.remote.client import main
File "/nix/store/izj1dw63bqh47bq10v1b2d7qqg9al7f7-python3.9-labgrid-0.4.1/lib/python3.9/site-packages/labgrid/__init__.py", line 1, in <module>
from .target import Target
File "/nix/store/izj1dw63bqh47bq10v1b2d7qqg9al7f7-python3.9-labgrid-0.4.1/lib/python3.9/site-packages/labgrid/target.py", line 9, in <module>
from .driver import Driver
File "/nix/store/izj1dw63bqh47bq10v1b2d7qqg9al7f7-python3.9-labgrid-0.4.1/lib/python3.9/site-packages/labgrid/driver/__init__.py", line 4, in <module>
from .serialdriver import SerialDriver
File "/nix/store/izj1dw63bqh47bq10v1b2d7qqg9al7f7-python3.9-labgrid-0.4.1/lib/python3.9/site-packages/labgrid/driver/serialdriver.py", line 5, in <module>
from packaging import version
ModuleNotFoundError: No module named 'packaging'
7fb99b7216