Fix typo.

Author: grokys

src/GitHub.Api/ApiClientConfiguration.cs

@@ -63,13 +63,13 @@ static string GetMachineIdentifier()
             try
             {
                 // adapted from http://stackoverflow.com/a/1561067
-                var fastedValidNetworkInterface = NetworkInterface.GetAllNetworkInterfaces()
+                var fastestValidNetworkInterface = NetworkInterface.GetAllNetworkInterfaces()
                     .OrderByDescending(nic => nic.Speed)
                     .Where(nic => nic.OperationalStatus == OperationalStatus.Up)
                     .Select(nic => nic.GetPhysicalAddress().ToString())
                     .FirstOrDefault(address => address.Length >= 12);
 
-                return fastedValidNetworkInterface ?? GetMachineNameSafe();
+                return fastestValidNetworkInterface ?? GetMachineNameSafe();
             }
             catch (Exception)
             {