improvement: use string not number for amount type in json schema

lib/ash_money/types/money.ex

@@ -284,9 +284,13 @@ defmodule AshMoney.Types.Money do
       %{
         type: "object",
         properties: %{
-          amount: %{type: "number"},
+          amount: %{type: "string", pattern: "^-?\\d+(\\.\\d+)?$"},
           currency: %{type: "string"}
         },
+        example: %{
+          amount: "100.00",
+          currency: "USD"
+        },
         required: ["amount", "currency"]
       }
     end