Test: Github extension

[chrmarti]

Testing #28631

• Windows - @bpasero
• Linux - @chrisdias
• Mac - @weinand

Complexity 2.

• Install the GitHub extension: https://marketplace.visualstudio.com/items?itemName=ms-vscode.github-issues-prs
• Check it uses the Git credentials manager from the Git repository in the opened folder to show the issues for the two upcoming milestones assigned to you.
• If your username cannot be determined through the Git credentials manager, everyones issues will be shown.
• If there are no milestones, all issues are shown (max. 100).
• Use github.username setting to show other user's issues / work around Git credentials manager not having your actual username.
• Test with a private repository.

[bpasero]

I tested on Windows because Linux does not work for me (#29555). @chrisdias I am moving Linux to you so that you can maybe sit together with @chrmarti why it does not work on Linux.

[chrisdias]

i'm running on linux and it does not work for me there either.