Show & check exporter version

Scripts/Meta/Editor/VRMMetaEditor.cs

@@ -79,6 +79,14 @@ namespace VRM
 
             so.Update();
 
+            GUI.enabled = false;
+            EditorGUILayout.PropertyField(m_propMap["ExporterVersion"]);
+            if (VRMVersion.IsNewer(m_propMap["ExporterVersion"].stringValue))
+            {
+                EditorGUILayout.HelpBox("Check UniVRM new version. https://github.com/dwango/UniVRM/releases", MessageType.Warning);
+            }
+            GUI.enabled = true;
+
             m_foldoutInfo = EditorGUILayout.Foldout(m_foldoutInfo, "Information");
             if (m_foldoutInfo)
             {

Scripts/Meta/VRMMetaObject.cs

@@ -5,6 +5,9 @@ namespace VRM
 {
     public class VRMMetaObject : ScriptableObject
     {
+        [SerializeField]
+        public string ExporterVersion;
+
         #region Info
         [SerializeField]
         public string Title;