SP-729 Support .NET 8.0

Author: mwarzybok-sumoheavy

BitPay/Clients/BillClient.cs

@@ -147,7 +147,11 @@ public async Task<List<Bill>> GetBills(string? status = null)
         /// <throws>BitPayApiException BitPayApiException class</throws>
         public async Task<Bill> UpdateBill(Bill bill, string billId)
         {
-            if (bill == null) BitPayExceptionProvider.ThrowMissingParameterException();
+            if (bill == null)
+            {
+                BitPayExceptionProvider.ThrowMissingParameterException();
+                throw new InvalidOperationException();
+            }
 
             string json = null!;
 

Directory.Build.props

@@ -2,6 +2,6 @@
     <PropertyGroup>
         <Nullable>enable</Nullable>
         <LangVersion>latest</LangVersion>
-        <TargetFrameworks>netstandard2.0;net6.0;net7.0;net8.0</TargetFrameworks>
+        <TargetFrameworks>net48;net6.0;net7.0;net8.0</TargetFrameworks>
     </PropertyGroup>
 </Project>