[VOL-5429] - update voltha-lib-go version to 7.6.6

Change-Id: Iff363d4cf9948b89d5520e101d2ac0912e3abb83
Signed-off-by: Sridhar Ravindra <sridhar.ravindra@radisys.com>
diff --git a/VERSION b/VERSION
index bb8dc63..00fc4bb 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.5.6
+4.5.7