Update copyright

Author: mnadareski

BurnOutSharp/BurnOutSharp.nuspec

@@ -10,7 +10,7 @@
     <projectUrl>https://github.com/mnadareski/BurnOutSharp</projectUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>Port of BurnOut to C#, with additions</description>
-    <copyright>Copyright (c)2005-2010 Gernot Knippen, Copyright (c)2018-2019 Matt Nadareski</copyright>
+    <copyright>Copyright (c)2005-2010 Gernot Knippen, Copyright (c)2018-2020 Matt Nadareski</copyright>
     <tags>protection scan burnout</tags>
     <dependencies>
       <dependency id="LessIO" version="0.5.0" />