[VOL-4290] Voltha go library updates for gRPC migration

Change-Id: I1aa2774beb6b7ed7419bc45aeb53fcae8a8ecda0
diff --git a/vendor/github.com/rcrowley/go-metrics/.travis.yml b/vendor/github.com/rcrowley/go-metrics/.travis.yml
index aead076..ce9afea 100644
--- a/vendor/github.com/rcrowley/go-metrics/.travis.yml
+++ b/vendor/github.com/rcrowley/go-metrics/.travis.yml
@@ -11,6 +11,9 @@
     - "1.10"
     - "1.11"
     - "1.12"
+    - "1.13"
+    - "1.14"
+    - "1.15"
 
 script:
     - ./validate.sh