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/demo_test/vendor/google.golang.org/protobuf/proto/wrappers.go b/demo_test/vendor/google.golang.org/protobuf/proto/wrappers.go
new file mode 100644
index 0000000..653b12c
--- /dev/null
+++ b/demo_test/vendor/google.golang.org/protobuf/proto/wrappers.go
@@ -0,0 +1,29 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+// Bool stores v in a new bool value and returns a pointer to it.
+func Bool(v bool) *bool { return &v }
+
+// Int32 stores v in a new int32 value and returns a pointer to it.
+func Int32(v int32) *int32 { return &v }
+
+// Int64 stores v in a new int64 value and returns a pointer to it.
+func Int64(v int64) *int64 { return &v }
+
+// Float32 stores v in a new float32 value and returns a pointer to it.
+func Float32(v float32) *float32 { return &v }
+
+// Float64 stores v in a new float64 value and returns a pointer to it.
+func Float64(v float64) *float64 { return &v }
+
+// Uint32 stores v in a new uint32 value and returns a pointer to it.
+func Uint32(v uint32) *uint32 { return &v }
+
+// Uint64 stores v in a new uint64 value and returns a pointer to it.
+func Uint64(v uint64) *uint64 { return &v }
+
+// String stores v in a new string value and returns a pointer to it.
+func String(v string) *string { return &v }