Fix SharedResources due to .NET 3.0 breaking change

More info at dotnet/aspnetcore#17733

src/CodingMilitia.PlayBall.Auth.Web/Pages/Login.cshtml.cs

@@ -1,7 +1,6 @@
 using System.ComponentModel.DataAnnotations;
 using System.Threading.Tasks;
 using CodingMilitia.PlayBall.Auth.Web.Data;
-using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.RazorPages;

src/CodingMilitia.PlayBall.Auth.Web/ResourcePlaceholders/SharedResource.cs

@@ -0,0 +1,8 @@
+// ReSharper disable once CheckNamespace - moved just because can't be on the same folder as the actual resources
+// https://github.com/dotnet/aspnetcore/issues/17733
+namespace CodingMilitia.PlayBall.Auth.Web
+{
+    public class SharedResource
+    {
+    }
+}