This includes a new `--registry` flag to the `dist-tag` command and defaults it to Wombat. This way NPM commands will explicitly use the correct registry.
We can't guarantee that the user provided these options at compile time, so all options should include `undefined` in their types. This makes the type system a little smarter and hopefully prevent future mistakes. Fortunately we were already doing the right thing, this will make sure we continue to do so in the future.
I opted to use `Partial<DistTagArgs>` so that all future flags would be implicitly forced to be optional. Otherwise, we may forget to make them optional and potentially introduce a bug.
