Added missing test file.

Author: sdanyliv

Tests/LinqToDB.EntityFrameworkCore.PostgreSQL.Tests/Models/NpgSqlEntities/EntityWithXmin.cs

@@ -0,0 +1,14 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+
+namespace LinqToDB.EntityFrameworkCore.PostgreSQL.Tests.Models.NpgSqlEntities
+{
+	public class EntityWithXmin
+	{
+		[Key]
+		public int Id { get; set; }
+
+		public uint xmin { get; set; }
+		public string Value { get; set; } = null!;
+	}
+}