progressbar required when using click integrations even if progressbar integration not used

[RhetTbull]

Even if progressbar is not used, using the click integration requires that progressbar be installed otherwise error: "ModuleNotFoundError: No module named 'progressbar'" is produced.

It seems that progressbar shouldn't be required if not being used.

OS: Mac OS 10.15.7 Python: Anaconda, Python 3.9.1 (default, Dec 11 2020, 06:28:49) bitmath: bitmath 1.3.3.1

>>> import click
>>> import bitmath
>>> from bitmath.integrations.bmclick import BitmathType
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/rhet/anaconda3/envs/osxphotos/lib/python3.9/site-packages/bitmath/integrations.py", line 29, in <module>
    import progressbar.widgets
ModuleNotFoundError: No module named 'progressbar'