Move .flake8 config to pyproject.toml

[AlexanderHott]

As of flake8 0.5.0 (hikari uses 0.5.4), you are able to define the flake8 configuration inside of the pyproject.toml file via the Flake8-pyproject flake8 plugin.

This upgrade drops support for flake8-broken-line, but black already removes any backslashes.

Black prefers parentheses over backslashes, and will remove backslashes if found.
(source)

The .flake8 file currently lists IFSTMT001 as one of the ignored codes, which I think should be IFS001, but hikari doesn't even use that flake8 plugin so it can just be removed. The 6 letter then 3 number code causes Flake8-pyproject to error, that's why I'm bringing this up.

All other tool configs are defined in the pyproject.toml, so I see no issue in moving it. I'd be happy to create a PR if this idea gets approved.

[davfsa]

The .flake8 file currently lists IFSTMT001 as one of the ignored codes, which I think should be IFS001, but hikari doesn't even use that flake8 plugin so it can just be removed. The 6 letter then 3 number code causes Flake8-pyproject to error, that's why I'm bringing this up.

This is just a left-over from when we had the plugin enabled

The 6 letter then 3 number code causes Flake8-pyproject to error, that's why I'm bringing this up.

That is the reason we initially disabled it.

All other tool configs are defined in the pyproject.toml, so I see no issue in moving it. I'd be happy to create a PR if this idea gets approved.

Feel free to!