Use default SslProtocols in Kestrel

Author: halter73

src/Servers/Kestrel/Core/src/HttpsConnectionAdapterOptions.cs

@@ -24,7 +24,6 @@ public class HttpsConnectionAdapterOptions
         public HttpsConnectionAdapterOptions()
         {
             ClientCertificateMode = ClientCertificateMode.NoCertificate;
-            SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls11;
             HandshakeTimeout = TimeSpan.FromSeconds(10);
         }
 
@@ -61,7 +60,8 @@ public HttpsConnectionAdapterOptions()
         public Func<X509Certificate2, X509Chain, SslPolicyErrors, bool> ClientCertificateValidation { get; set; }
 
         /// <summary>
-        /// Specifies allowable SSL protocols. Defaults to <see cref="SslProtocols.Tls12" /> and <see cref="SslProtocols.Tls11"/>.
+        /// Specifies allowable SSL protocols. Defaults to <see cref="SslProtocols.None" /> which allows the operating system to choose the best protocol to use,
+        /// and to block protocols that are not secure. Unless your app has a specific reason not to, you should use this default.
         /// </summary>
         public SslProtocols SslProtocols { get; set; }