[VOL-2875]v3 Update version for 2.3 branch

Change-Id: I1e603f8216f2f99e3ae62d7b0fcc5cbf3066426d
diff --git a/.gitreview b/.gitreview
index 94a12ba..35222a1 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,3 +3,4 @@
 port=29418
 project=voltha-docs.git
 defaultremote=origin
+defaultbranch=voltha-2.3