[main] Update dependencies from mono/linker

[dotnet-maestro]

This pull request updates the following dependencies

From https://github.com/mono/linker

• Subscription: 0d6d6ae4-f71f-4395-53e6-08d8e409d87d
• Build: 20210429.1
• Date Produced: 4/29/2021 8:51 PM
• Commit: 307f6b0afd2fea639fffa97e67155bafe6aa8461
• Branch: refs/heads/main

• Updates:
  • Microsoft.NET.ILLink.Tasks: from 6.0.100-preview.2.21226.1 to 6.0.100-preview.5.21229.1

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[marek-safar]

@vitek-karas it looks like the linker SDK bump will need to be reverted and wait till P5 bump is propagated

[vitek-karas]

This makes the roundtrip terribly long. We added a public API into runtime a week ago. We want to use it the linker. But we have to wait for the runtime to update its SDK build - which is done like once every 3 months...
In this case it's even worse - in order to correctly support the new API we need the linker changes in place... so we'll have runtime in this weird semi-broken state for multiple months...

[marek-safar]

I agree with you but that's, unfortunately, the setup infra team has been pushing hard for the slow updates. There is a scheduled monthly update #51716 but right now it's way behind on what is needed here.