Option to create the output directory when it doesn't exists

[0x26res]

TLDR: can we add an option to create the directory of the output_path (or make it the default to create it if it doesn't exists).

For context, I don't use the generated protobuf directly, I typically put them in a wheel and use them in another package in the same repository. I also don't track them in git.

Typically when I generate this type of "generated" source, I put them in a build directory. And by default these directories are ignored because build is in my .gitignore. Most other tool that operate on the build directory know to create the directory if it doesn't exists.