Add support for libman v3 files in Microsoft.Web.LibraryManager.Build

[djarrettsompo]

Is your feature request related to a problem? Please describe.

When using libman in a fresh .NET 9 Blazor project on VS 17.12, it creates v3 libman files by default. If you Enable Client-Side Libraries on Build and run a build you will get this error in VS:

Version "3.0" is not supported by this version of Library Manager

Describe the solution you'd like

Microsoft.Web.LibraryManager.Build to support v3 files so that no error is generated on build

Describe alternatives you've considered

As a workaround, changing the libman file to v1 results in a successful build but I'm unsure of the long-term repercussions of this.

[djarrettsompo]

Apologies, but this may be a duplicate of #769

[djarrettsompo]

Also looks like this was/is resolved in #756 , so I guess the real question is when will this be released?