This pull request updates the `protocgen.sh` script to insert the `go_package` option to all of the downloaded proto files. A related pull request into the spec repo removes this options from the .proto files: https://github.com/tendermint/spec/pull/358
This pull requests, along with the related spec PR, aim to move the creation of the `tendermintdev/docker-build-proto` container into the spec repo. This change also relies on several fixes to that container that are made in the PR into the spec repo.