PGPy compatibility break with Python < 3.8

[MarcinGinszt]

6e34a00
This commit uses the logging.debug function with keyword argument stacklevel.
stacklevel in this library is allowed as a keyword argument for Python versions >= 3.8
https://docs.python.org/3/library/logging.html?highlight=stacklevel
Changed in version 3.8: The stacklevel parameter was added.
Running this code on Python 3.6 results in an error

  | File "/opt/app-root/lib/python3.6/site-packages/pgpy/decorators.py", line 104, in usage
  | "".format(**em), stacklevel=4)
  | File "/usr/lib64/python3.6/logging/__init__.py", line 1912, in debug
  | root.debug(msg, *args, **kwargs)
  | File "/usr/lib64/python3.6/logging/__init__.py", line 1296, in debug
  | self._log(DEBUG, msg, args, **kwargs)
  | TypeError: _log() got an unexpected keyword argument 'stacklevel'

[J-M0]

Hey @MarcinGinszt, thanks for the report! Would you mind sharing some example code that triggers this? I'd like to make a test.

[MarcinGinszt]

Any code using PGPKey.encrypt() will fail. Thanks!

[J-M0]

Can you provide a more detailed sample please? I know the parameter isn't in older Python versions, but I'm having trouble triggering the bug.

[J-M0]

Nevermind, I got it