use assembly file version instead of product version for update check

ModpackUpdater/AppUpdater.vb

@@ -1,5 +1,6 @@
 Imports System.IO
 Imports System.Net.Http
+Imports System.Reflection
 
 Imports Newtonsoft.Json
 Imports Newtonsoft.Json.Converters
@@ -21,10 +22,11 @@ Public Class AppUpdater
         Dim hasUpdate As Boolean = False
 
         Try
+            Dim appVersion As Version = Assembly.GetExecutingAssembly().GetName().Version
             Dim result = Await httpClient.GetStringAsync(UPDATE_URL)
             info = JsonConvert.DeserializeObject(Of UpdateInfo)(result)
 
-            If info IsNot Nothing AndAlso info.Version < New Version(Application.ProductVersion) Then
+            If info IsNot Nothing AndAlso info.Version < appVersion Then
                 hasUpdate = True
             End If
         Catch ex As Exception