Merge pull request #489 from Merglasch/EarlyInit

Earlier intialization for Unitask, depending on unity version

src/UniTask/Assets/Plugins/UniTask/Runtime/PlayerLoopHelper.cs

@@ -285,7 +285,11 @@ namespace Cysharp.Threading.Tasks
             return dest.ToArray();
         }
 
+#if UNITY_2020_1_OR_NEWER
+		[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterAssembliesLoaded)]
+#else
 		[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
+#endif
         static void Init()
         {
             // capture default(unity) sync-context.