docs: Added CITATION.cff, updated citation info

CITATION.cff

@@ -0,0 +1,27 @@
+cff-version: 1.2.0
+message: "If you use Vicinity in your research, please cite it as below."
+title: "Vicinity: Lightweight Nearest Neighbors with Flexible Backends"
+authors:
+  - family-names: "Tulkens"
+    given-names: "Stephan"
+  - family-names: "van Dongen"
+    given-names: "Thomas"
+doi: 10.5281/zenodo.17265874
+license: MIT
+url: "https://github.com/MinishLab/vicinity"
+repository-code: "https://github.com/MinishLab/vicinity"
+date-released: "2024-11-09"
+
+preferred-citation:
+  type: software
+  title: "Vicinity: Lightweight Nearest Neighbors with Flexible Backends"
+  authors:
+    - family-names: "Tulkens"
+      given-names: "Stephan"
+    - family-names: "van Dongen"
+      given-names: "Thomas"
+  year: 2024
+  publisher: Zenodo
+  doi: 10.5281/zenodo.17265874
+  url: "https://github.com/MinishLab/vicinity"
+  license: MIT

README.md

@@ -198,3 +198,19 @@ pip install vicinity[voyager]
 ## License
 
 MIT
+
+## Citing
+
+If you use Vicinity in your research, please cite the following:
+
+```bibtex
+@software{minishlab2024vicinity,
+  author       = {Stephan Tulkens and {van Dongen}, Thomas},
+  title        = {Vicinity: Lightweight Nearest Neighbors with Flexible Backends},
+  year         = {2024},
+  publisher    = {Zenodo},
+  doi          = {10.5281/zenodo.17265874},
+  url          = {https://github.com/MinishLab/vicinity},
+  license      = {MIT}
+}
+```