dependencies: update to latest versions

[ldennington]

GCM has several key dependencies that have become outdated. Before our next
release (slated just ahead of Git's 2.41 release cycle), we should update these
dependencies to the latest stable versions available. These include:

• Avalonia
  • Repo
  • NuGet package
• MSAL
  • Repo
  • NuGet packages

[ldennington]

MSAL was updated with #1191 and Avalonia was updated with #1207