docs: update list of contributors

PR-URL: 	#1135
Reviewed-by: Athan Reines <kgryte@gmail.com>
Co-authored-by: Philipp Burckhardt <pburckhardt@outlook.com>

CONTRIBUTORS

@@ -9,6 +9,7 @@ Brendan Graetz <bguiz@users.noreply.github.com>
 Bruno Fenzl <brunofenzl@gmail.com>
 Christopher Dambamuromo <chridam@gmail.com>
 Dan Rose <danoftheroses@gmail.com>
+Daniel Killenberger <daniel.killenberger@gmail.com>
 Dominik Moritz <domoritz@gmail.com>
 Dorrin Sotoudeh <dorrinsotoudeh123@gmail.com>
 Frank Kovacs <fran70kk@gmail.com>