Update gerrit version for mac to 2.13.6

Change-Id: I43051b0c13f2d83068949532be7e6284557fcad5
diff --git a/macOS/Makefile b/macOS/Makefile
index 25d61d0..713197b 100644
--- a/macOS/Makefile
+++ b/macOS/Makefile
@@ -1,4 +1,4 @@
-VERSION := 2.13.5
+VERSION := 2.13.6
 
 all: server
 
diff --git a/macOS/README.md b/macOS/README.md
index b019e99..f8f7377 100644
--- a/macOS/README.md
+++ b/macOS/README.md
@@ -8,5 +8,5 @@
 ```
   $ chmod a+x scripts/*
   $ chmod a+x uninstaller/scripts/*
-  $ make VERSION=2.13.5
+  $ make VERSION=2.13.6
 ```