HttpClient.cs

using System;
using System.IO;
using System.Net;
using System.Windows.Forms;

namespace Updater
{
    class HttpClient
    {
        public string Get(string uri)
        {
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
            ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
            ServicePointManager.DefaultConnectionLimit = 9999;

            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
                request.UserAgent = "request";
                using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                using (Stream stream = response.GetResponseStream())
                using (StreamReader reader = new StreamReader(stream))
                {
                    return reader.ReadToEnd();
                }
            }
            catch (WebException ex)
            {
                //MessageBox.Show(string.Format("{0}: {1}", ex.ToString(), ex.Message), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                MessageBox.Show("Unable to contact Github.Try again later.", "No valid Github response", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return null;
            }
        }
    }
}