Updated the nlog dependency

Author: niemyjski

Source/Platforms/NLog/NuGet/Exceptionless.NLog.nuspec

@@ -14,7 +14,7 @@
     <tags>NLog Target Exceptionless Error Report Reporting Exception Logging Log ELMAH</tags>
     <dependencies>
       <dependency id="Exceptionless.Portable" version="[$version$]" />
-      <dependency id="NLog" version="3.2" />
+      <dependency id="NLog" version="4.2.1" />
     </dependencies>
   </metadata>
 </package>