install protobuf; make test script executable

Jenkinsfile

@@ -6,7 +6,9 @@ pipeline {
         checkout scm
         script {
           docker.image("golang:1.14-alpine").inside {
-            sh './test.sh'
+            sh "apk add --no-cache protobuf-dev"
+            sh "go get -u github.com/golang/protobuf/protoc-gen-go"
+            sh "./test.sh"
           }
         }
       }