Bump actions/setup-node from 5 to 6

Bumps [actions/setup-node](https://github.com/actions/setup-node) from 5 to 6.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-node
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -23,7 +23,7 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm ci
@@ -72,7 +72,7 @@ jobs:
       - uses: actions/download-artifact@v5
         with:
           name: build
-      - uses: actions/setup-node@v5
+      - uses: actions/setup-node@v6
         with:
           node-version: 20.x
       - uses: rlespinasse/github-slug-action@v3.x
@@ -94,7 +94,7 @@ jobs:
       - uses: actions/download-artifact@v5
         with:
           name: build
-      - uses: actions/setup-node@v5
+      - uses: actions/setup-node@v6
         with:
           node-version: 20.x
       - name: Disable pre- and post-publish actions