The custom setuptools_scm configuration is removed. It was buggy (for
the case of a dirty worktree exactly at the tag, it did not append
`+dirty`) and otherwise is only different from node-and-timestamp by
appending `.dirty` instead of `.dYYYYMMDDHHMMSS`. The latter is
preferable anyway.
This reverts commit 7fca037f9c.
This broke editable installs and has to be reverted due to a number
of pip issues:
* pypa/pip#6375
* pypa/pip#6434
* pypa/pip#6438
We can put this back once PEP 517/518 support editable installs.
Until then the legacy behavior will suffice, and we should just teach
people to install the dependencies in virtualenvs or something...