put CITATION.bib back with one entry (JuliaLang#40956)

With a link to https://julialang.org/research for more papers to cite.

CITATION.bib

@@ -0,0 +1,15 @@
+% This article is the definitive citation for Julia.
+@article{Julia-2017,
+ title={Julia: A fresh approach to numerical computing},
+ author={Bezanson, Jeff and Edelman, Alan and Karpinski, Stefan and Shah, Viral B},
+ journal={SIAM {R}eview},
+ volume={59},
+ number={1},
+ pages={65--98},
+ year={2017},
+ publisher={SIAM},
+ doi={10.1137/141000671},
+ url={https://epubs.siam.org/doi/10.1137/141000671}
+}
+
+% For more details on research related to Julia, see https://julialang.org/research