File nuget.config of Package playtest

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <packageSources>
        <add key="LocalNugetPackages" value="./LocalNugetPackages" />
    </packageSources>
    <disabledPackageSources>
        <add key="nuget.org" value="true" />
    </disabledPackageSources>
</configuration>