Add CITATION.cff

[ErikDanielsson]

Added a CITATION.cff in accordance with #361

PR checklist

• This comment contains a description of changes (with reason)
• CHANGELOG.md is updated
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated

[codecov]

Codecov Report

Merging #1663 (cfcd83e) into dev (0cc0a0a) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev    #1663   +/-   ##
=======================================
  Coverage   64.43%   64.43%           
=======================================
  Files          56       56           
  Lines        6574     6574           
=======================================
  Hits         4236     4236           
  Misses       2338     2338           

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[sdruskat]

Please note that the file must be called CITATION.cff to be a valid CFF file (and be picked up by GitHub and downstream clients).

[ErikDanielsson]

Thank you - I didn't spot that!

[mirpedrol]

👍