Exception: Calling TargetGuidByName with name=’Unity-iPhone’ is deprecated. There are two targets now, call GetUnityMainTargetGuid()

非推奨になったライブラリが対応してもらうまでに
先に修正して対応。

	//string target = proj.TargetGuidByName("Unity-iPhone");
#if UNITY_2019_3_OR_NEWER
	string target = proj.GetUnityFrameworkTargetGuid();
#else
	string target = proj.TargetGuidByName(PBXProject.GetUnityTargetName());
#endif