MANIFEST.in may not be needed with setuptools_scm

[niksirbi]

I have stumbled upon some information that MANIFEST.in is no longer needed when using setuptools_scm. This is because setuptools_scm, by default includes all version-controlled files in the sdist.
To learn more about this see the following:

• Helpful blogpost
• Stack overflow thread
• GitHub issue

Thought @adamltyson ? Getting rid of MANIFEST.in would mean that all git-tracked files (and only those) are included in the sdist. Is that a sensible thing to do?

If we don't get rid of it, I am not sure we still get the behaviour we want, due to how this interacts with setuptools_scm (see the linked issue)

[adamltyson]

I think we need to look into this, because there's lots of stuff that's in the repo that's shouldn't be in the sdist (test data in particular).
I read the blog that states everything in the repo should be in sdist, but I don't agree. The sdist isn't used for development, it's used for installation when there's no wheel available.

I think we'll always need to tool to determine what gets packaged and what doesn't.