docs: missing DOI and citation in `refs.bib`

[wang-boyu]

Hi, I'm reviewing your JOSS paper and found some missing info in your references. More specifically -

• DOI is missing for paper "Schulze, J., Müller, B., Groeneveld, J., & Grimm, V. (2017). Agent-based modelling of social-ecological systems: Achievements, challenges, and a way forward. Journal of Artificial Societies and Social Simulation, 20(2), 8."
• The paper cited Mesa-Geo but it's not included in the refs.bib file.

On a side note, it would be nice if you could format the references is a consistent way, either all in title case, or all in sentence case, but not a mix of both. For example,

Sentence case: Beckage, B., Moore, F. C., & Lacasse, K. (2022). Incorporating human behaviour into Earth system modelling. ...

Title Case: Beckage, B., Moore, F. C., & Lacasse, K. (2022). Incorporating Human Behaviour into Earth System Modelling. ...

But this is not strictly required; just something nice to have for your own consideration. It's not blocking the paper review.

[jamesdamillington]

On line 99 of the JOSS proof there is a reference to wang2022 that is missing (this may be the same reference @wang-boyu refers to in their second bullet point). Please add this reference.

[SongshGeo]

Thanks for the explanation by @jamesdamillington; yep, the reference to mesa-geo was not rendered because it lacked a bib item. It would be arrogant if I totally ignored mesa-geo but invited @wang-boyu to review this repo, LOL.

The behavior of the case-sensitive problem was because when exporting the .bib file, a 'keep case' option was selected.

Now everything is fixed in PR #38.