VOL-3616: Update version of voltha-protos to 4.0.4

Change-Id: Id1cbfe0a96b831c0bea57c81a46629a9f50b9638
diff --git a/VERSION b/VERSION
index 3704213..c5106e6 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.0.3-dev
+4.0.4