Added ReadAdditionalTypesNullable

ExcelORM/ExcelORMTests/ReaderTests.cs

@@ -127,4 +127,12 @@ public class ReaderTests
         var results = reader.Read<TestAdditionalTypes>().ToArray();
         Assert.NotEmpty(results);
     }
+    
+    [Fact]
+    public void ReadAdditionalTypesNullable()
+    {
+        using var reader = new ExcelReader(AdditionalTypes);
+        var results = reader.Read<TestAdditionalTypesNullable>().ToArray();
+        Assert.NotEmpty(results);
+    }
 }

ExcelORM/ExcelORMTests/TestAdditionalTypesNullable.cs

@@ -0,0 +1,7 @@
+namespace ExcelORMTests;
+
+public record TestAdditionalTypesNullable
+{
+    public TestEnum? MyEnum {get; set;}
+    public Guid? MyGuid {get; set;}
+}