chpass-wrapper.py helper script for password plugin appears to be broken with python 3.9

[sdondley]

Can someone more knowledgeable with python please take a look at this:

https://stackoverflow.com/a/70051629/1641112

I'd be happy to supply a commit to patch this but I read about 2 chapters of a python book 10 years ago and haven't touched it since. If someone can confirm this a good fix, I'll do a pull request. Thanks.

[alecpl]

Fixed.

The text argument does not work with Python < 3.7, so we have to use an alias universal_newlines. I tested the change on python 2.7 and 3.6.