Add Unity 2020.3.4f1 (#12520)

manifests/u/UnityTechnologies/Unity/2020.3.4f1/UnityTechnologies.Unity.yaml

@@ -0,0 +1,23 @@
+PackageIdentifier: UnityTechnologies.Unity
+PackageVersion: 2020.3.4f1
+PackageName: Unity Editor
+Publisher: UnityTechnologies
+License: Copyright © 2021 Unity Technologies Inc
+LicenseUrl: https://unity3d.com/legal
+ShortDescription: "Break the barriers of reality –â\x81  bring new ideas to life with Unity."
+Moniker: unity
+Tags:
+- unity
+- game engine
+- .NET
+- C#
+- unity3d
+PackageUrl: https://unity.com/
+Installers:
+- Architecture: x64
+  InstallerUrl: https://download.unity3d.com/download_unity/0abb6314276a/Windows64EditorInstaller/UnitySetup64-2020.3.4f1.exe
+  InstallerSha256: 4FC17237C882649EC65A76BFC50A5F20C0C04153F346AF04EA013F9436BA99EC
+  InstallerType: nullsoft
+PackageLocale: en-US
+ManifestType: singleton
+ManifestVersion: 1.0.0