Updating flake8 for python 3.8

Now that we have adopted python 3.8 we need to change the version of the flake8 linting tool that we are using on GitHub and in conda. The new flake8 adds a new warning for f-strings that do not include any variables so we can’t simply upgrade it without some breakage.

The plan is:

  • Update the GitHub actions so that they will use the new flake8
  • Fix things as needed when pull requests are made
  • Once all packages pass update conda.

Until we do this our code can not use the walrus operator (:=).

If you make a PR and it fails the lint test before I’ve got around to fixing it, you are welcome to fix the problem on your PR. From a quick analysis I think this will only be a problem for afw, pipe_tasks, meas_base and cp_pipe so I will fix those up a soon as possible.