Bump actions/checkout off the deprecated v4 in @danielridgebot's workflows

In hackforla/check-ghpages-versions, inspect .github/workflows/check-gh-pages-version.yml, check-ruby-version.yml, keepalive.yml, and test-issue-labels.yml. Find each uses: actions/checkout entry and update only the four requested versions, then run keepalive.yml via workflow_dispatch. Done means checkout succeeds without a Node 20 annotation; a scheduled version-check run should be confirmed after the merge.

Overview

We need to bump actions/checkout from v4 to v5 in all four of @danielridgebot's workflows, because v4 targets Node.js 20 and GitHub is force-running it on Node 24 on every run — when that fallback is withdrawn the workflows break, and this bot's failure mode is silence rather than an alert.

Action Items

The bot's code lives in hackforla/check-ghpages-versions — the org repo, not a personal account (the danielridgebot/check-ghpages-versions URL still resolves, but only as a redirect). The fix is one line per file, delivered as a PR on that repo.

• Bump actions/checkout@v4 to actions/checkout@v5 in all four workflows: check-gh-pages-version.yml:13, check-ruby-version.yml:13, keepalive.yml:16, test-issue-labels.yml:11. Line numbers were accurate 2026-08-24 and may drift — find them by the uses: actions/checkout line.
• Leave actions/github-script@v8 alone (line 44 of both check workflows). It already runs on Node 24 and produces no annotation.
• Do not go past v5 in this pass, even though v7 is current. v5 is the pure Node 24 bump with no behaviour change. v6 moved the persisted git credential into a separate file, and three of these four workflows depend on that credential to git push a commit back to the repo. v7 additionally blocks fork checkouts for pull_request_target/workflow_run. Both are probably fine here, but neither is a one-line change any more — going current is a separate ticket that needs a real push test.
• Run keepalive.yml on the branch via workflow_dispatch and confirm the checkout step succeeds with no Node 20 annotation. It is safe to run at any time: it prints the repo's idle age and exits 0 without committing unless the repo has been idle 50 or more days.
• After the PR merges, confirm a scheduled run of check-gh-pages-version.yml or check-ruby-version.yml completes with no "Node.js 20 is deprecated" annotation. Both run daily (12:00 and 12:15 UTC), so this is a next-day check — it cannot be observed from the branch, because the annotation only appears on the runs that actually do the version check.

Resources/Instructions

• Bot repo: https://github.com/hackforla/check-ghpages-versions — workflows are in .github/workflows/.
• Example of the annotation: https://github.com/hackforla/check-ghpages-versions/actions/runs/32782593141 (check-ruby-version, 2026-08-24) — "Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4".
• Release notes, for the version reasoning above: v5.0.0 (Node 24; requires runner v2.327.1+, which GitHub-hosted runners are well past), v6.0.0, v7.0.0.
• A full end-to-end test exists but has side effects and is not needed for this change: setting release-versions/github-pages-gem.txt to an older value and dispatching check-gh-pages-version.yml exercises the git push path, but it also opens a real issue on hackforla/devops with a board card, which then has to be closed and the card deleted.
• Related: #180 (re-enabled the bot's disabled workflow and added the keepalive).