Fix CITATION.cff and add automatic validation of your citation metadata

[abelsiqueira]

Hello!

We noticed that your CITATION.cff had a small issue and fixed it.

In addition to the fix, this Pull Request automates validation of that file using the cffconvert GitHub Action. That way, it's a little bit easier to be robust against future changes to the CITATION.cff file.

BTW it's perfectly fine if you don't feel like accepting this Pull Request for whatever reason -- we just thought it might be helpful is all.

We found your repository using a partially automated workflow; if you have any questions about that, feel free to create an issue over at https://github.com/cffbots/filtering/issues/

On behalf of the cffbots team,
@abelsiqueira / @fdiblen / @jspaaks

[eddiebergman]

Hi @abelsiqueira,

Many thanks! I tried running a manual validator against this before which came up fine but glad to see a workflow for it. As this is based on our older master branch, I will take these changes into a seperate PR from the most recent development but I will make sure to give proper attribution!

Best,
Eddie