SEBA-902 single-olt tests;
Pin protoc-gen-go to 1.3.2 to resolve compatibility issue;
Run go mod tidy / go mod vendor on importer;
Add Go Module support to demotest

Change-Id: Ifde824fc9a6317b0adc1e12bea54ee1f9b788906
diff --git a/vendor/github.com/rcrowley/go-metrics/.travis.yml b/vendor/github.com/rcrowley/go-metrics/.travis.yml
index 117763e..aead076 100644
--- a/vendor/github.com/rcrowley/go-metrics/.travis.yml
+++ b/vendor/github.com/rcrowley/go-metrics/.travis.yml
@@ -1,13 +1,16 @@
 language: go
 
 go:
-    - 1.3
-    - 1.4
-    - 1.5
-    - 1.6
-    - 1.7
-    - 1.8
-    - 1.9
+    - "1.3"
+    - "1.4"
+    - "1.5"
+    - "1.6"
+    - "1.7"
+    - "1.8"
+    - "1.9"
+    - "1.10"
+    - "1.11"
+    - "1.12"
 
 script:
     - ./validate.sh