Due to .NET Core SDK issue #1021, our meta-package project Microsoft.PowerShell.SDK starts to generate an empty assembly during the build and that results in an empty assembly Microsoft.PowerShell.SDK.dll appear in publish folder and in .deps.json file. We cannot simply remove the assembly because it's now part of the TPA, and removing it will cause powershell to crash at startup. We have to live with this empty assembly until that .NET Core SDK issue is fixed.
This issue is opened to track this .NET Core SDK issue on our side.