[fix] 修复 StripAOTDllCommand由于缓存原因，有些情况下生成失败的问题。通过添加BuildOptions.CleanBuildCache选项解决。此选项在Unity 2021及更高版本新增。

Editor/Commands/StripAOTDllCommand.cs

@@ -38,6 +38,9 @@ namespace HybridCLR.Editor.Commands
             BashUtil.RemoveDir(outputPath);
 
             var buildOptions = BuildOptions.BuildScriptsOnly;
+#if UNITY_2021_1_OR_NEWER
+            buildOptions |= BuildOptions.CleanBuildCache;
+#endif
 
             bool oldExportAndroidProj = EditorUserBuildSettings.exportAsGoogleAndroidProject;
 #if UNITY_EDITOR_OSX