Ignore Flake8's W503

[Julian-O]

Flake8 has a rule: Line break occurred before a binary operator (W503).

By default, Flake8 does not apply this rule, because it is a bad rule, and the Flake8 authors know it:

This rule goes against the PEP 8 recommended style, which was changed on April 16th, 2016 in this commit. The tool will soon be updated to recommend the opposite: line breaks should occur before the binary operator because it keeps all operators aligned.

In January, Buildozer's config was changed to start applying this rule.

This is painful to me, because I use black wherever I can (and heartily recommend Kivy projects move towards adopting it), and black-formatted code does not conform to this rule.

Please remove this rule from the Buildozer config (i.e. return it to the ignore list)

[misl6]

Fixed via #1660