add link.xml

Assets/link.xml

@@ -0,0 +1,5 @@
+<linker>
+    <assembly fullname="UnityEngine">
+        <type fullname="UnityEngine.TrailRenderer" preserve="all"/>
+    </assembly>
+</linker>

Assets/link.xml.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 39f639190c60a064cad65eec409f8812
+TextScriptImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: