Set Gerrit to 3.0.0-rc0 for MacOS package

Change-Id: Iba18ca872278d230d26825a1915e7888a4fefe0a
diff --git a/macOS/Makefile b/macOS/Makefile
index 631c5c8..e77b6d4 100644
--- a/macOS/Makefile
+++ b/macOS/Makefile
@@ -1,4 +1,4 @@
-VERSION := 2.16.5
+VERSION := 3.0.0-rc0
 
 all: server