fix ci/cd error (#2428)

src/Discord.Net.Core/Discord.Net.Core.csproj

@@ -16,7 +16,6 @@
     <PackageReference Include="IDisposableAnalyzers" Version="3.4.15">
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="System.ValueTuple" Version="4.5.0" />
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.1' ">
     <PackageReference Include="System.Collections.Immutable" Version="1.3.1" />
@@ -27,4 +26,7 @@
   <ItemGroup Condition=" '$(TargetFramework)' == 'net461' ">
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
   </ItemGroup>
+  <ItemGroup Condition=" '$(TargetFramework)' != 'net461'">
+    <PackageReference Include="System.ValueTuple" Version="4.5.0" />
+  </ItemGroup>
 </Project>