Add JOSS citation

[ml-evs]

🎉

[codecov]

Codecov Report

Merging #949 (4d5b79e) into master (31cf41a) will not change coverage.
The diff coverage is n/a.

❗ Current head 4d5b79e differs from pull request most recent head b4bf639. Consider uploading reports for the commit b4bf639 to get more accurate results

@@           Coverage Diff           @@
##           master     #949   +/-   ##
=======================================
  Coverage   92.78%   92.78%           
=======================================
  Files          67       67           
  Lines        3786     3786           
=======================================
  Hits         3513     3513           
  Misses        273      273           

Flag	Coverage Δ
project	92.78% <ø> (ø)
validator	92.78% <ø> (ø)

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[CasperWA]

Yay 🎉

[CasperWA]

🎉