Adds token name constant

Author: gislikonrad

src/Solid.Identity.Protocols.Saml2p/Middleware/Sp/FinishSsoEndpointMiddleware.cs

@@ -174,7 +174,7 @@ public async Task<FinishSsoResult> FinishSsoAsync(HttpContext context)
 
                 var authn = new AuthenticationToken
                 {
-                    Name = "saml2",
+                    Name = Saml2pConstants.TokenName,
                     Value = validateContext.Response.XmlSecurityToken
                 };
                 properties.StoreTokens(new[] { authn });

src/Solid.Identity.Protocols.Saml2p/Saml2pConstants.cs

@@ -2,6 +2,7 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
+using Microsoft.AspNetCore.Authentication;
 
 namespace Solid.Identity.Protocols.Saml2p
 {
@@ -10,6 +11,11 @@ namespace Solid.Identity.Protocols.Saml2p
     /// </summary>
     public static class Saml2pConstants
     {
+        /// <summary>
+        /// The name of the token that is stored in <see cref="AuthenticationProperties"/>.
+        /// </summary>
+        public const string TokenName = "saml2";
+        
         internal const string DateTimeFormat = "yyyy-MM-ddTHH:mm:ss.fffZ";
 
 #pragma warning disable CS1591 // Missing XML comment for publicly visible type or member