Mark all Options parameters as optional

[qtiki]

Currently the types enforce you to either A) provide no options or B) provide a value for every option. In reality they all have default values and can be left "undefined" so they should be optional in the types too.

[qtiki]

I was going to open an issue about this but then I figured it's such an easy fix I'll just do the PR. Basically the types as they are now can break TypeScript compilation for users of this library when they update, which is what happened to us. We are using only the cwd option but the compiler throws an error about it.

[tianhuil]

@Klathmon -- any update on this?

[scottbot95]

Any update on this? I'm currently using patch-package to patch this fix in.