Edit a Booking

[xShirokuma]

Update and return an existing booking.

• An authenticated user is required for a successful response
• Only the owner of the booking is authorized to edit
• Booking record is updated in the database after request
• Booking data returned includes the id, userId, spotId, startDate,
  endDate, createdAt, and updatedAt
• Error response with status 404 is given when a booking does not exist with
  the provided id
• Error response with status 400 is given when it is past the booking's
  endDate (no editing of past bookings)
• Error response with status 403 is given when a booking already exists for
  the spot on the specified dates