Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: '18.20.8'
           check-latest: true
@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: '18.20.8'
           check-latest: true
@@ -47,7 +47,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node }}
           check-latest: true

.github/workflows/gh-pages.yml

@@ -23,7 +23,7 @@ jobs:
         working-directory: website
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 18.20.8
           cache: 'npm'