Add support for the new optional fields API

[vmarcosp]

Hey team!
First off, thanks for your awesome work and contributions to the rescript ecosystem ❤️

I'm using this ppx to build the new version of Ancestor and one ppx that could save me a lot of work is partial. However, partial doesn't support the new optional fields api introduced on the rescript @ v10.
Are you planning to add support for the new optional fields api? If so, can I help you with this feature?

[mununki]

@vmarcosp Hey!
Thank you for using this ppx.
Sure, it would support the optional field record. I couldn't grab the time to fix it yet. PR is always welcome! 👍

[vmarcosp]

Nice!
Sure, I can help with this issue :)
Are you planning to keep supporting both apis using ?: and option or should we create a second partial implementation?

[mununki]

Good question!
I think the partial ppx should support the ? not option<'a> which is now possible with the new feature of v10. I prefer not to make a breaking change, but this time breaking would be okay.
What do you think?

[vmarcosp]

I agree, it's ok to me make a breaking since ppl can still using the current version instead of migrating to a new one.