Change request url for Vattenfall API automatically every day

[Steve-Mcl]

1. Put a function node before the HTTP Request node containing...

   const today = new Date()
   const tomorrow = new Date(today)
   tomorrow.setDate(tomorrow.getDate() + 1)
   const yyyy = tomorrow.getFullYear();
   const mm = (tomorrow.getMonth() + 1).toString().padStart(2, "0");
   const dd = tomorrow.getDate().toString().padStart(2,"0");
   msg.url = `https://www.vattenfall.se/api/price/spot/pricearea/${yyyy}-${mm}-${dd}/${yyyy}-${mm}-${dd}/SN3`
   return msg;
   

2. Clear the http request node URL property so that is uses msg.url from the function