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

Author: renovate[bot]

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Extract node version
         run: echo "NODE_VERSION=$(cat .node_version)" >> $GITHUB_ENV
       - name: Set Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ env.NODE_VERSION }}
           cache: npm

.github/workflows/publish_gh_pages.yml

@@ -16,7 +16,7 @@ jobs:
         with:
           fetch-depth: 1
       - name: Use Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 22.x
       - name: Build page