[GRASS-git] [OSGeo/grass-addons] fa646d: GitHub action: added flake8 tests (#399)

[Markus Neteler]

  Branch: refs/heads/master
  Home:   https://github.com/OSGeo/grass-addons
  Commit: fa646d7724b00b2fdad6fe95ae8256335fa10b8d
      https://github.com/OSGeo/grass-addons/commit/fa646d7724b00b2fdad6fe95ae8256335fa10b8d
  Author: Markus Neteler <neteler at gmail.com>
  Date:   2021-02-17 (Wed, 17 Feb 2021)

  Changed paths:
    A .github/workflows/flake8.yml
    A grass7/.flake8
    A grass7/gui/wxpython/.flake8

  Log Message:
  -----------
  GitHub action: added flake8 tests (#399)

* GitHub action: added flake8 tests

yml file:
workflows/flake8.yml: copied from https://github.com/OSGeo/grass/blob/master/.github/workflows/flake8.yml

The .flake8 files have been copied from:
- gui/wxpython/.flake8: copied from https://github.com/OSGeo/grass/blob/master/gui/wxpython/.flake8
- all others: copied from https://github.com/OSGeo/grass/blob/master/scripts/.flake8
* flake8: use centralized config file
- ignore F405
- use centralized `.flake8` config file, except for `gui/wxpython/`
* fix path in flake8-gui-wxgui-scripts
* flake8: ignore F403 and W605
* flake8: ignore F403 and W605; alpha-order
* flake8.yml: simplify using matrix
* wxgui: use v2 ; remove unneeded temporal/.flake8
* flake8.yml: partial sync to flake8.yml in GRASS-core
* partial sync to https://github.com/OSGeo/grass/pull/1309
* Apply suggestions from code review
* Expand flake8 ignore lists

Co-authored-by: Carmen <carmen.tawalika at gmail.com>