launcherTemplate.gradle in unity 2020.1.0b2

### Please fill in the following fields:
Unity editor version: 2020.1.0b2
External Dependency Manager version:
Features in External Dependency Manager in use : Android Resolver
Plugins SDK in use (Firebase, Admob, Facebook, etc.): Firebase, Admob, OneSignal
Platform you are using the Unity editor on : Windows
Platform you are targeting : Android
Scripting Runtime : IL2CPP

### Please describe the issue here:
Since unity 2019.3 unity had changed their build system to build the main project as library. Which affect android related to `manifest.xml` and `.gradle` because we now has 2 gradle folders, for launcher and library, and all of the previous version has a bug that they don't allow us to override them in project

This bug was fixed in https://unity3d.com/unity/beta/2020.1.0b2

> Android: Allow to overwrite gradle.properties file, as well as main and launcher manifests, base, launcher and main gradle templates. Default templates can be added to project by enabling checkboxes in Player Settings > Publishing Settings

### Please answer the following, if applicable:
100%

Alternatively, you might consider switching all resolver system tobe `IPostGenerateGradleAndroidProject` (as of #308 )
What would be your preference?