A few ASP.NET Core packages that used to be installed via DotNetCliToolReference will be built-in commands for the CLI. When invoking "dotnet watch" now, it will use the built-in version, not the one delivered via DotNetCliToolReference, so DotNetCliToolReference should be removed.
cref aspnet/Announcements#290.

Since we don't have a proper way to issue obsolete messages about packages (NuGet/Home#2867), can we add a target that runs before Restore that issues an obsolete warning for the following packages

<ItemGroup>
   <DotNetCliToolReference Include="Microsoft.DotNet.Watcher.Tools" Version="(all versions)" />
   <DotNetCliToolReference Include="Microsoft.Extensions.SecretManager.Tools" Version="(all versions)" />
   <DotNetCliToolReference Include="Microsoft.Extensions.Caching.SqlConfig.Tools" Version="(all versions)" />
</ItemGroup>

Proposed text:

warning SDK0000: the DotNetCliToolReference to Microsoft.DotNet.Watcher.Tools is obsolete. This tool is now bundled in the CLI. The DotNetCliToolReference can be removed.