Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/secretlint-only-on-changed-files.yml

@@ -13,7 +13,7 @@ jobs:
         uses: actions/checkout@v5
       - uses: technote-space/get-diff-action@v6
       - name: setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 16
       - name: Install

.github/workflows/secretlint.yml

@@ -10,7 +10,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v5
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 16
       - name: Install