Add the QED-it report to the acknowledgements.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/protocol.tex

@@ -9732,7 +9732,7 @@ Michael Dixon, Andrew Poelstra, and no doubt others. We would also like to
 thank the designers and developers of \Bitcoin.
 
 \Zcash has benefited from security audits performed by NCC Group, Coinspect,
-Least Authority, Mary Maller, and Kudelski Security.
+Least Authority, Mary Maller, Kudelski Security, and QED-it.
 
 The Faerie Gold attack was found by Zooko Wilcox; subsequent analysis
 of variations on the attack was performed by Daira Hopwood and Sean Bowe.
@@ -9789,6 +9789,7 @@ Peter Newell's illustration of the Jubjub bird, from \cite{Carroll1902}.
             \item Improved cross-referencing in \crossref{concretepedersenhash}.
           \end{itemize}
 } %sapling
+    \item Add the QED-it report to the acknowledgements.
 \end{itemize}
 
 \introlist