Ver.2.1.0

This release is compatible with Unity 2020.2.
Previous versions are broken in 2020.2 so require to update if you use Unity 2020.2.

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Add UnityWebRequestException.ResponseHeaders
Add PlayerLoopTiming.TimeUpdate/LastTimeUpdate in Unity 2020.2
Force complete awaiting JobHandles when quitted in UnityEditor Cysharp#196, thanks @RamType0
Suppress allocations around UniTask.AsUniTask and UniTask.AsAsyncUnitUniTask Cysharp#203, thanks @RamType0
Accept calling DeferPromise.GetStatus multiple times Cysharp#204, thanks @piti6
Unity 2020.2 changed order of the PlayerLoop subsystem list (should fix Cysharp#208) Cysharp#210, thanks @WallyCZ
Fix DelayType.Realtime does not work when use BuildPlayer in UnityEditor