chore(internal/gapicgen): update protoc-gen-go
github.com/googleapis/gapic-generator-go@v0.15.3 from github.com/googleapis/gapic-generator-go/cmd/protoc-gen-go_gapic@v0.15.3 requires github.com/golang/protobuf@v1.4.3
@@ -29,7 +29,7 @@ RUN go version
# Install Go tools.
RUN GO111MODULE=on go get \
- github.com/golang/protobuf/protoc-gen-go@v1.4.2 \
+ github.com/golang/protobuf/protoc-gen-go@v1.4.3 \
golang.org/x/lint/golint@latest \
golang.org/x/tools/cmd/goimports@latest \
honnef.co/go/tools/cmd/staticcheck@latest \
