Bump protobuf to 3.6.1 to support newer features

.travis.yml

@@ -6,7 +6,7 @@ services:
 
 env:
   global:
-    - PROTOC_RELEASE="https://github.com/google/protobuf/releases/download/v3.5.1/protoc-3.5.1-linux-x86_64.zip"
+    - PROTOC_RELEASE="https://github.com/google/protobuf/releases/download/v3.6.1/protoc-3.6.1-linux-x86_64.zip"
     - PROTOC_TARGET="${HOME}/protoc"
     - PATH="${PROTOC_TARGET}/bin:${PATH}"
     - secure: Tbet2rxD8QgjthAo+bxt41qbF2wUPTx0difGK5p4yQISK/njTuT5cqcxnOa4GIbyKtNtx0EgGnyVcQJiQkmZiF6Sabf0mtqU/CQ4PmVV76e9bHwA/CrTtudibMn16ozxuuxvhNxFOMQEhwcQOkW93M/Q9FZUEw9/CGpRGFfSzuA=

Dockerfile

@@ -1,13 +1,13 @@
 FROM debian:jessie-slim
-LABEL maintainer="pseudomuto <david.muto@gmail.com>" protoc_version="3.5.1"
+LABEL maintainer="pseudomuto <david.muto@gmail.com>" protoc_version="3.6.1"
 
 WORKDIR /
 
-ADD https://github.com/google/protobuf/releases/download/v3.5.1/protoc-3.5.1-linux-x86_64.zip ./
+ADD https://github.com/google/protobuf/releases/download/v3.6.1/protoc-3.6.1-linux-x86_64.zip ./
 RUN apt-get -q -y update && \
   apt-get -q -y install unzip && \
-  unzip protoc-3.5.1-linux-x86_64.zip -d ./usr/local && \
-  rm protoc-3.5.1-linux-x86_64.zip && \
+  unzip protoc-3.6.1-linux-x86_64.zip -d ./usr/local && \
+  rm protoc-3.6.1-linux-x86_64.zip && \
   apt-get remove --purge -y unzip && \
   apt-get autoremove && \
   rm -rf /var/lib/apt/lists/*

Gopkg.toml

@@ -31,7 +31,7 @@
 
 [[constraint]]
   name = "github.com/golang/protobuf"
-  version = "^1.0.0"
+  version = "^1.1.0"
 
 [[constraint]]
   name = "github.com/pseudomuto/protokit"

examples/proto/Customer.proto

@@ -3,6 +3,8 @@ syntax = "proto2";
 
 package com.example;
 
+option ruby_package = "com.example.ruby";
+
 // Use // or /** */ to document messages, fields and enums.
 
 /**