Update 'grpc-gateway' and 'genproto' dependencies.

Gopkg.lock

Gopkg.toml

...thub.com/grpc-ecosystem/grpc-gateway/.circleci/Dockerfile

...ithub.com/grpc-ecosystem/grpc-gateway/.circleci/README.md

...thub.com/grpc-ecosystem/grpc-gateway/.circleci/config.yml

vendor/github.com/grpc-ecosystem/grpc-gateway/.gitignore

...or/github.com/grpc-ecosystem/grpc-gateway/.goreleaser.yml

vendor/github.com/grpc-ecosystem/grpc-gateway/.travis.yml

...ub.com/grpc-ecosystem/grpc-gateway/.travis/bazel-build.sh

...hub.com/grpc-ecosystem/grpc-gateway/.travis/bazel-test.sh

....com/grpc-ecosystem/grpc-gateway/.travis/install-bazel.sh

...com/grpc-ecosystem/grpc-gateway/.travis/install-protoc.sh

...ecosystem/grpc-gateway/.travis/install-swagger-codegen.sh

vendor/github.com/grpc-ecosystem/grpc-gateway/BUILD

vendor/github.com/grpc-ecosystem/grpc-gateway/CHANGELOG.md

...or/github.com/grpc-ecosystem/grpc-gateway/CONTRIBUTING.md

vendor/github.com/grpc-ecosystem/grpc-gateway/Gopkg.lock

vendor/github.com/grpc-ecosystem/grpc-gateway/Gopkg.toml

.../github.com/grpc-ecosystem/grpc-gateway/ISSUE_TEMPLATE.md

vendor/github.com/grpc-ecosystem/grpc-gateway/Makefile