Summary of the new feature/enhancement

As a developer consuming NuGet packages, I want the license terms of each package to remain readable and immutable after I have reviewed them. However, PowerShell NuGet packages such as Microsoft.PowerShell.Security currently have https://github.com/PowerShell/PowerShell/blob/master/LICENSE.txt as licenseUrl in the package metadata. The license terms referenced by such a URL can be changed, and the URL may stop working if the branch is renamed (as requested in #12951).

Proposed technical implementation details (optional)

NuGet has deprecated licenseUrl (NuGet/Announcements#32). The license property should be used instead, presumably here: