Add net5.0-windows build on x86 apps for now.

samples/Sample.Net5Winform/Program.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace Sample.Net5Winform
+{
+    static class Program
+    {
+        /// <summary>
+        ///  The main entry point for the application.
+        /// </summary>
+        [STAThread]
+        static void Main()
+        {
+            Application.SetHighDpiMode(HighDpiMode.SystemAware);
+            Application.EnableVisualStyles();
+            Application.SetCompatibleTextRenderingDefault(false);
+            Application.Run(new TestForm());
+        }
+    }
+}