fix: add preprocessor directives

src/StevanFreeborn.Extensions.Configuration.Secure/Cryptography/MachineIdKeyProvider.cs

@@ -11,7 +11,11 @@ internal sealed class MachineIdKeyProvider(IMachineIdKeyGenerator generator) : I
   {
     var machineId = _generator.GetId();
     var @bytes = Encoding.UTF8.GetBytes(machineId);
+#if NET5_0_OR_GREATER
+    return SHA256.HashData(@bytes);
+#else
     using var sha256 = SHA256.Create();
     return sha256.ComputeHash(@bytes);
+#endif
   }
 }