VOL-1613 VERSION file on voltha-go

Change-Id: I34aae02e99f9e5421fa4f505d7a646f16314bf6a
diff --git a/Makefile b/Makefile
index 754763b..79f4baa 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,9 @@
 
 SHELL=/bin/bash -e -o pipefail
 
+# Variables
+VERSION			?= $(shell cat ./VERSION)
+
 ifeq ($(TAG),)
 TAG := latest
 endif