Missing PublishDir from Microsoft.Build.CommonTypes.xsd

When you publish an app through VS (at least in some paths), it writes a FolderProfile.pubxml. I guess it is imported into the build. If you open that to look at it or edit it you will get a warning in VS
```
Severity Code Description Project File Line Suppression State
Warning The element 'PropertyGroup' in namespace 'http://schemas.microsoft.com/developer/msbuild/2003' has invalid child element 'PublishDir' in namespace 'http://schemas.microsoft.com/developer/msbuild/2003'. List of possible elements expected: 'Property, VisualStudioVersion, MinimumVisualStudioVersion, ........ etc etc, .... ConsoleApp9 C:\Users\danmose\source\repos\ConsoleApp9\ConsoleApp9\Properties\PublishProfiles\FolderProfile.pubxml 9
```

Here is an example of a FolderProfile.pubxml:
```

Release
Any CPU
bin\Release\netcoreapp3.1\publish\
FileSystem

```

I am not sure whether there are other properties it might include, but we should add `PublishDir` and `PublishProtocol` to Microsoft.Build.CommonTypes.xsd so they don't cause this disconcerting warning which will discourage anyone looking at the file.