BREAKING CHANGE: remove py2 support

[jochman]

I've removed typed-ast package at there are problems with this package in apple-silicon.
Also, typed ast recommends using the builtin ast module from python 3.8 and up.

I could not understand why the uts are failing, I would like to get help to fix those.

[jochman]

@usagitoneko97 Hey, what's up?

[jochman]

@usagitoneko97 alive mate?

[tristanlatr]

Hi @jochman,

Would it possible to keep the python dependency at python 3.6 and still use the standard ast library? We should handled gracefully the fact that type annotations from comments are not available in python 3.6 and 3.7.

Also there are many more code to cleanup while dropping support for python2. Maybe this can be done later, though.

Are you willing to fork this library and continue maintaining it? I would be down to add support for imports and define a higher level api interface. If you want we can create an organization to host a new repository for klara.

Tell me what you think.
Thank