chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/build-verify.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 20
           cache: npm

.github/workflows/gh-pages-deploy.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 20
           cache: npm