Add software citation source

Author: jakewilliami

README.md

@@ -25,3 +25,7 @@ To get the latest version of `splunk-mode`, clone this repository and then use:
 (add-to-list 'load-path "<path to splunk mode>")
 (require 'splunk-mode)
 ```
+
+## Citation
+
+If your research depends on `splunk-mode`, please consider giving us a formal citation: [`citation.bib`](./citation.bib).

citation.bib

@@ -0,0 +1,7 @@
+@software{ireland2024splunkmode,
+  title={\texttt{splunk-mode}: Syntax highlighting for {Splunk} in {Emacs}},
+  author={Ireland, Jake W},
+  year={2024},
+  howpublished={\url{https://github.com/jakewilliami/splunk-mode}},
+  note={{Emacs Lisp} package version 1.1.0}
+}