remove unnecessary reference to steamkit2

Author: Rudokhvist

ASFAchievementManager/ASF-Achievement-Manager.csproj

@@ -12,12 +12,6 @@
     <PackageReference Include="System.Composition.AttributedModel" Version="*" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Reference Include="SteamKit2">
-      <HintPath>..\ArchiSteamFarm\ArchiSteamFarm\lib\SteamKit2.dll</HintPath>
-    </Reference>
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\ArchiSteamFarm\ArchiSteamFarm\ArchiSteamFarm.csproj" />
   </ItemGroup>