Bump actions/setup-node from 4 to 5 in /.github/actions/bootstrap (#1845)

Bumps [actions/setup-node](https://github.com/actions/setup-node) from 4 to 5.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v4...v5)

---
updated-dependencies:
- dependency-name: actions/setup-node
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/actions/bootstrap/action.yml

@@ -38,7 +38,7 @@ runs:
         echo "full-version=${REPO_VERSION}" >> $GITHUB_OUTPUT
         echo "major-version=$(echo ${REPO_VERSION} | cut -d"." -f1)" >> $GITHUB_OUTPUT
         
-    - uses: actions/setup-node@v4
+    - uses: actions/setup-node@v5
       with:
         cache: npm
         cache-dependency-path: src/Elastic.Documentation.Site/package-lock.json