Updated citation.

README.md

@@ -25,7 +25,8 @@ arXiv preprint arXiv:2301.08047, 2023.
   title={Data-driven kernel designs for optimized greedy schemes: A machine learning perspective},
   author={Wenzel, Tizian and Marchetti, Francesco and Perracchione, Emma},
   journal={arXiv preprint arXiv:2301.08047},
-  year={2023}
+  year={2023},
+  note={Accepted for publication in SISC.}
 }
 ```