Update actions/setup-node action to v6 (#342)

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

Author: renovate[bot]

.github/workflows/commenter.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Use Node.js
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@v6
     - run: npm install
     - run: |
         node lib/comment.js --diff | tee -a results.txt

.github/workflows/npm-publish.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Use Node.js
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@v6
       with:
         registry-url: 'https://registry.npmjs.org'
     - run: |