RFR: 8295714: GHA ::set-output is deprecated and will be removed

[Aleksey Shipilev]

On Thu, 20 Oct 2022 10:00:14 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> We need to transition to use the new `$GITHUB_OUTPUT` method instead. 
> 
> This needs to be fixed since it is currently spamming the summary with warnings, and will stop working soon.

Thanks! Looks fine, provided GHAs are green.

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Marked as reviewed by shade (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10785