Discount webhook topics and types are missing

[sleepdotexe]

Hi there,

I noticed that some of the available webhook topics do not have type definitions for either the topic or payload resource. Particularly important ones include:

• discounts/create
• discounts/delete
• discounts/redeemcode_added
• discounts/redeemcode_removed
• discounts/update

The reference for these can be found in the Shopify docs here. I believe this relates to the topic type definition starting on this line and payload type map starting on this line.

Could we please have types added for these?

Thank you!

[lpinca]

Feel free to open a PR.