Poetry: Integrate setuptools-scm

[RonnyPfannschmidt]

Basic idea is instead of replicating scm metadata, just take them from the scm

I'm happy to ensure setuptools is no longer a hard dependency

[madig]

https://github.com/sdispater/poetry/issues/140 :)

[RonnyPfannschmidt]

@madig for extra context - im the maintainer of setuptools_scm and im willing to change it so setuptools wont be required for use from poetry

[webknjaz]

I was just about to create another issue like #140 and #185 :)

@sdispater would you please comment on this? I'd be interested in contributing as well.

[webknjaz]

btw I'd bundle it with https://github.com/Changaco/setuptools_scm_git_archive

[webknjaz]

Let's close this in favor of #140 + #672 (demo discussion) so that it would be 1 single place with info, not 3 issues asking the same :)

[stephsamson]

Closing this in favor of #693.