use types instead of interfaces

lib/getServerSideProps.ts

@@ -2,13 +2,13 @@ import { startOfYear } from 'date-fns'
 import { nowInTz } from '../helpers/date'
 import { getBookingByUUID, getBookings } from '../db/index'
 
-export interface ServerSideBooking {
+export type ServerSideBooking = {
   props: {
     booking: object
   }
 }
 
-export interface ServerSideRecentBooking {
+export type ServerSideRecentBooking = {
   props: {
     bookings: object[]
   }

lib/session.ts

@@ -5,7 +5,7 @@ export enum USER_ROLE {
   ADMIN = 'admin',
 }
 
-export interface UserData {
+export type UserData = {
   username: string
   role: USER_ROLE
 }