CORD-2772 set version number for onos service

Change-Id: I801262dbb49fca5eb3855d6486a21340428cd15e
diff --git a/VERSION b/VERSION
new file mode 100644
index 0000000..519af9a
--- /dev/null
+++ b/VERSION
@@ -0,0 +1 @@
+6.0.0.dev