Consider publishing a dual packaged module?#14

I'm trying to use this package inside oclif, but I'm hitting [this error](https://github.com/oclif/oclif/issues/695). Essentially it doesn't support loading es modules. Despite the fact that this module is TypeScript and my code is TypeScript, the modules won't play nice. I don't fully understand the ins and outs. I guess that you're only publishing an ESM module which is the latest and greatest, and oclif is using some older module loading strategy which won't play nice. Question, would you be open to publishing a dual build module? For inspiration, I've been able to import [tsdav](https://github.com/natelindev/tsdav) without issue in oclif.