close #464 Fixed: 0 Money payment in invoice and bill;

Transfer,
Bill, Bill Payment, Bill Total,
Payment,
Invoice, Invoice Payment, Invoice Total,
Revenue.

app/Http/Requests/Income/InvoiceTotal.php

@@ -26,7 +26,7 @@ class InvoiceTotal extends Request
         return [
             'invoice_id' => 'required|integer',
             'name' => 'required|string',
-            'amount' => 'required',
+            'amount' => 'required|amount',
             'sort_order' => 'required|integer',
         ];
     }