You should automatically close all issues when a new version is released.

If the issue isn't being taken care of, it may be no longer be relevant once a new vscode version is released.

I suggest you should :

1. Automatically mark new issues with the current vscode version.
2. When a new version is released, close all previous vscode version issues.

Let the author eventually reopen the issue, bumping the issue marker.

This should help preventing to go through issues that are no longer relevant.
If you didn't have time to analyze an issue, it may be reopened / duplicated by the author / someone else.
When someone else opens a new issue which duplicates a closed one, keep the new one open and bump its priority has it is being reported by multiple people.

An issue may be long-standing : add a long-standing marker to prevent auto close. This marker could eventually automatically be added if the issue is being reopened over X versions.