Adding CITATION.cff file for proper citation.

CITATION.cff

+cff-version: "1.2.0"
+authors:
+- family-names: Malou
+  given-names: Thibault
+  orcid: "https://orcid.org/0009-0002-3540-8789"
+- family-names: Labarthe
+  given-names: Simon
+  orcid: "https://orcid.org/0000-0002-5463-7256"
+contact:
+- family-names: Labarthe
+  given-names: Simon
+  orcid: "https://orcid.org/0000-0002-5463-7256"
+doi: 10.5281/zenodo.13834137
+message: If you use this software, please cite our article in the
+  Journal of Open Source Software.
+preferred-citation:
+  authors:
+  - family-names: Malou
+    given-names: Thibault
+    orcid: "https://orcid.org/0009-0002-3540-8789"
+  - family-names: Labarthe
+    given-names: Simon
+    orcid: "https://orcid.org/0000-0002-5463-7256"
+  date-published: 2024-09-26
+  doi: 10.21105/joss.06863
+  issn: 2475-9066
+  issue: 101
+  journal: Journal of Open Source Software
+  publisher:
+    name: Open Journals
+  start: 6863
+  title: "Pherosensor-toolbox: a Python package for Biology-Informed
+    Data Assimilation"
+  type: article
+  url: "https://joss.theoj.org/papers/10.21105/joss.06863"
+  volume: 9
+title: "Pherosensor-toolbox: a Python package for Biology-Informed Data
+  Assimilation"
\ No newline at end of file