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/Shopify/sarama/produce_request.go b/vendor/github.com/Shopify/sarama/produce_request.go
index 0c755d0..178972a 100644
--- a/vendor/github.com/Shopify/sarama/produce_request.go
+++ b/vendor/github.com/Shopify/sarama/produce_request.go
@@ -214,6 +214,8 @@
 		return V0_10_0_0
 	case 3:
 		return V0_11_0_0
+	case 7:
+		return V2_1_0_0
 	default:
 		return MinVersion
 	}