Minor fixes: (improbable-eng#237)

Regenerate Gopkg.lock with new dep.
Add protoc-gen-go as explicit dependency.
Install stable version of dep in CI.
Install dep locked version of protoc-gen-go in CI.

.travis.yml

@@ -1,6 +1,6 @@
 language: go
 go:
-  - 1.8
+  - "1.11"
 go_import_path: github.com/improbable-eng/grpc-web
 addons:
   hosts:
@@ -44,14 +44,16 @@ before_install:
   - true && `base64 --decode <<< ZXhwb3J0IEJST1dTRVJfU1RBQ0tfVVNFUk5BTUU9aW1wcm9iYWJsZWVuZ2JvdDEK`
   - true && `base64 --decode <<< ZXhwb3J0IEJST1dTRVJfU1RBQ0tfQUNDRVNTX0tFWT1SRG1Cc2pwQUJ4RlljcEVkeVp5bwo=`
 install:
-  - go get -u github.com/golang/dep/cmd/dep
   - go get -u golang.org/x/tools/cmd/goimports
   - go get -u github.com/robertkrimen/godocdown/godocdown
+  - curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
   - dep ensure
+  - go install ./vendor/github.com/golang/protobuf/protoc-gen-go
+  - export PATH=/home/travis/gopath/src/github.com/improbable-eng/grpc-web/protobuf/bin:$PATH
   - nvm install
   - npm install
 before_script:
   - ./test/start-testserver.sh &
 script:
   - ./lint-all.sh
-  - travis_retry npm run test
+  - travis_retry npm run test

Gopkg.toml

@@ -1,25 +1,6 @@
-
-# Gopkg.toml example
-#
-# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
-# for detailed Gopkg.toml documentation.
-#
-# required = ["github.com/user/thing/cmd/thing"]
-# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
-#
-# [[constraint]]
-#   name = "github.com/user/project"
-#   version = "1.0.0"
-#
-# [[constraint]]
-#   name = "github.com/user/project2"
-#   branch = "dev"
-#   source = "github.com/myfork/project2"
-#
-# [[override]]
-#  name = "github.com/x/y"
-#  version = "2.4.0"
-
+required = [
+  "github.com/golang/protobuf/protoc-gen-go",
+]
 
 [[constraint]]
   branch = "master"