ci: upgrade to actions/checkout@4 and actions/setup-node@4

Reference: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

.github/workflows/ci.yml

@@ -22,10 +22,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
 
@@ -54,10 +54,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Use Node.js 20
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version: 20