Use a more compatible NuGet.exe

tools/WebHooks.tasks.targets

@@ -76,7 +76,7 @@
                     {
                         Log.LogMessage("Downloading latest version of NuGet.exe...");
                         WebClient webClient = new WebClient();
-                        webClient.DownloadFile("https://dist.nuget.org/win-x86-commandline/v3.5.0/nuget.exe", OutputFileName);
+                        webClient.DownloadFile("https://dist.nuget.org/win-x86-commandline/v4.8.2/nuget.exe", OutputFileName);
                     }
 
                     return true;