RFR: 8315863: [GHA] Update checkout action to use v4

[Aleksey Shipilev]

On Thu, 7 Sep 2023 14:47:41 GMT, Christian Stein <cstein at openjdk.org> wrote:

> Please review this change to update all workflows to use `actions/checkout at v4`.
> 
> Find the associated release notes here: https://github.com/actions/checkout/releases/tag/v4.0.0

Oh, okay then!

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15620#pullrequestreview-1615778353