improved mp3 detection

[CatKasha]

fixes #139
references:
https://www.datavoyage.com/mpgscript/mpeghdr.htm
https://en.wikipedia.org/wiki/MP3#/media/File:Mp3filestructure.svg

[CatKasha]

cant pass flake8 tests, i give up, feel free to remove comments

[guigarfr]

You have the errors in the logs, just fix them and update the PR.

/home/runner/work/filetype.py/filetype.py/filetype/types/audio.py:46:5: E129 visually indented line with same indent as next logical line
/home/runner/work/filetype.py/filetype.py/filetype/types/audio.py:47:21: E117 over-indented
/home/runner/work/filetype.py/filetype.py/filetype/types/audio.py:55:5: E129 visually indented line with same indent as next logical line
/home/runner/work/filetype.py/filetype.py/filetype/types/audio.py:56:25: E117 over-indented

[CatKasha]

You have the errors in the logs, just fix them and update the PR.

Yea i saw it, E117 error was added with latest commit and idk how to fix E129 without make it looks ugly

[CatKasha]

Yay, thanks @MikhailMurashov for fixing flake issues

[MikhailMurashov]

@guigarfr can we merge it?

[guigarfr]

@MikhailMurashov I don't have any permissions to merge... I gues you'll need a reviewer or two approving so that can be merged? I don't know.

If it was me the reviewer i would say:

• fixup all commits in just one as there is just a single change (you wrote many commits!)
• that single commit should contain a test (that should fail with current library code) and your change (already does, which fixes it). So... where is the test that should have failed and is fixed with this code? (you should've added a new mp3 sample and created the required tests in https://github.com/h2non/filetype.py/tree/master/tests)

@h2non can someone else review this?