Retry a couple of times (#1360)

source/SkiaSharp.Build.targets

@@ -184,7 +184,7 @@ internal partial class VersionConstants {
           SourceFiles="@(_CopyItems)"
           DestinationFiles="@(_CopyItems -> '$(MSBuildThisFileDirectory)..\output\$(PackagingGroup)\%(Dest)')"
           ContinueOnError="false"
-          Retries="0" />
+          Retries="3" />
   </Target>
 
   <!--