link保留ET程序集防止裁剪 (#279)

2021.2以上版本打包IL2CPP或Mono开启裁剪，会导致Init加载MoveView时报空

Unity/Assets/link.xml

@@ -1,6 +1,10 @@
 <linker>
-  <assembly fullname="Unity.Model" preserve="all"/>
-  <assembly fullname="Unity.ThirdParty" preserve="all"/>
-  <assembly fullname="UnityEngine" preserve="all"/>
+    <assembly fullname="Unity.Hotfix" preserve="all"/>
+    <assembly fullname="Unity.HotfixView" preserve="all"/>
+    <assembly fullname="Unity.Model" preserve="all"/>
+    <assembly fullname="Unity.ModelView" preserve="all"/>
+    <assembly fullname="Unity.Mono" preserve="all"/>
+    <assembly fullname="Unity.ThirdParty" preserve="all"/>
+    <assembly fullname="UnityEngine" preserve="all"/>
   <assembly fullname="System" preserve="all"/>
 </linker>