VOL-4226: Bump to version 3.5.1 in preparation for voltha-2.8 release.
Also use voltha-lib-go version 5.0.5 to be in-sync with all other modules.

Change-Id: Ie6db02ea8266e2b55304176708e9d5480bcae06d
diff --git a/VERSION b/VERSION
index c1aee2f..d5c0c99 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.5.1-dev
+3.5.1