fix invalid version prop

Author: oleksandr-didyk

src/Microsoft.Build.Tasks.Tfvc/Microsoft.Build.Tasks.Tfvc.csproj

@@ -19,7 +19,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.Build" Version="$(MicrosoftBuildVersion)" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.Build.Tasks.Core" Version="$(MicrosoftBuildTasksCore)" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.Build.Tasks.Core" Version="$(MicrosoftBuildTasksCoreVersion)" PrivateAssets="all" />
     <PackageReference Include="Microsoft.TeamFoundationServer.ExtendedClient" Version="$(MicrosoftTeamFoundationServerExtendedClientVersion)" />
   </ItemGroup>
   <ItemGroup>