How do you publish in .NET 5.0?

[TonyValenti]

I have a brand new WPF app with this publishing profile:

<?xml version="1.0" encoding="utf-8"?>
<!--
https://go.microsoft.com/fwlink/?LinkID=208121. 
-->
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <Configuration>Release</Configuration>
    <Platform>Any CPU</Platform>
    <PublishDir>bin\publish\</PublishDir>
    <PublishProtocol>FileSystem</PublishProtocol>
    <TargetFramework>net5.0-windows</TargetFramework>
    <SelfContained>true</SelfContained>
    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
    <PublishSingleFile>False</PublishSingleFile>
    <PublishReadyToRun>False</PublishReadyToRun>
    <PublishTrimmed>False</PublishTrimmed>
  </PropertyGroup>
</Project>

When I try to publish, I get this error:

2>Assets file 'C:\Users\Tony Valenti\source\repos\WpfApp5\WpfApp5\obj\project.assets.json' doesn't have a target for 'net5.0-windows/win-x64'. Ensure that restore has run and that you have included 'net5.0-windows' in the TargetFrameworks for your project. You may also need to include 'win-x64' in your project's RuntimeIdentifiers.

What do I do?

[huoyaoyuan]

This looks like a clean build is not done before publishing.
And also, the ToolsVersion and xmlns may confuse some tooling to see it as legacy project format.