update mongoose to 5.8.3 (lots of types changes)

pages/api/bookings/[uuid]/bill.ts

@@ -1,5 +1,5 @@
 import { NextApiRequest, NextApiResponse } from 'next'
-import { Bill } from '../../../../db/bill'
+import { IBill } from '../../../../db/bill'
 import { createBill, patchBill } from '../../../../db/index'
 import { log } from '../../../../helpers/log'
 
@@ -13,7 +13,7 @@ export default async function billHandler(
   } = req
   const bookingUUID = Array.isArray(uuids) ? uuids[0] : uuids
 
-  let bill: Bill
+  let bill: IBill
 
   switch (method) {
     case 'POST':
@@ -40,4 +40,4 @@ export default async function billHandler(
       res.setHeader('Allow', ['POST', 'PATCH'])
       res.status(405).end(`Method ${method} Not Allowed`)
   }
-}
+}