There are some changes to the code generated in the latest version, so
this modifies every .pb.go file.
Also, the way protoc-gen-go decides where to put files has changed, so
each generate.go gets the --go_opt=paths=source_relative flag to
tell protoc to continue placing output next to the input.
Remove staticcheck from build.sh; we get it via golangci-lint now.
Pass --no-document to gem install fpm; this is recommended in the fpm docs.