Update actions/setup-node action to v6 (#26)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
       - uses: pnpm/action-setup@v4
         with:
           version: latest
-      - uses: actions/setup-node@v5
+      - uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}
           cache: pnpm

.github/workflows/publish_release.yml

@@ -25,7 +25,7 @@ jobs:
       - uses: pnpm/action-setup@v4
         with:
           version: latest
-      - uses: actions/setup-node@v5
+      - uses: actions/setup-node@v6
         with:
           node-version: 24
           registry-url: 'https://registry.npmjs.org'