Add problem matcher for NuGetAudit

[Falco20019]

Description:
https://learn.microsoft.com/en-us/nuget/concepts/auditing-packages is enabled by default and generating warnings NU1900-NU1905. It's possible to use -err: on them to fail the build on CI, but we would prefer to only have them as warnings appearing.

Justification:
Without matcher, they are hard to find. There already is a matcher for csc, so wouldn't be too far off to expect this creating annotations as-well.

Are you willing to submit a PR?
#605

[priyagupta108]

Hi @Falco20019 👋,
Thank you for the feature request, we will investigate it and get back to you as soon as we have some feedback.

[Falco20019]

Any update? It's been 2 months :)

[Falco20019]

@priyagupta108 Any update? The PR #605 is sadly still unreviewed. This would help us a lot!