docs: Add CITATION.cff Citation File Format file

[matthewfeickert]

Resolves #238

Add Citation File Format file to repo to get repository cite button on GitHub and citation support on Zenodo.

• c.f. https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/creating-a-repository-on-github/about-citation-files

The schema used is validated by cffconvert

$ pipx install cffconvert
$ cffconvert --validate --infile CITATION.cff 
Citation metadata are valid according to schema version 1.2.0.

[matthewfeickert]

In scikit-hep/hist#416 the CITATION.cff had to be excluded from the MANIFEST.in, but I don't know if anything like that needs to be done with hatchling.

[matthewfeickert]

Small reminder ping to @henryiii @jpivarski.

[codecov-commenter]

Codecov Report

Merging #243 (a936cc7) into main (b4531ed) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #243   +/-   ##
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  Coverage   82.63%   82.63%           
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  Files          96       96           
  Lines       10524    10524           
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  Hits         8697     8697           
  Misses       1827     1827           

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[henryiii]

the CITATION.cff had to be excluded from the MANIFEST.in

It should be in the SDist by default but not the wheel. Don't see harm in having it in the SDist, though it could be manually excluded if we want to. It's tool.hatch.sdist.exclude or something of that sort.

[Saransh-cpp]

It's tool.hatch.sdist.exclude or something of that sort.

[tool.hatch.build.targets.sdist]
exclude = [
  "./CITATION.cff"
]

should work!

https://hatch.pypa.io/latest/build/#configuration

[matthewfeickert]

While

[tool.hatch.build.targets.sdist]
exclude = [
  "/CITATION.cff"
]

does work to ignore it from the sdist

$ python -m build . && python -m tarfile --list dist/*.tar.gz | grep "CITATION.cff"
$ echo $?
1

I see that vector isn't ignoring any other files in the repo, and so for a single text file I don't think it is worth it to ignore the CITATION.cff. So I'll just leave this PR as adding the CITATION.cff only.

This should be ready for review from the 3 of you now.

[matthewfeickert]

As 2 of the authors have approved this I'm going to merge this.