incorrect path for copying steam_appid.txt

[Gillissie]

Based on the installation location in Unity, this path for copying steam_appid.txt is incorrect.
Perhaps it should either be:
Assets/com.rlabrecque.steamworks.net
or
Assets/Steamworks.NET/

public class RedistInstall {
static RedistInstall() {
CopyFile("Assets/Plugins/Steamworks.NET/redist", "steam_appid.txt", false);