github: bump actions per warning message

> Node.js 16 actions are deprecated. Please update the following actions to use
> Node.js 20: actions/checkout@v2, actions/setup-node@v2. For more information
> see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

.github/workflows/ci.yml

@@ -12,10 +12,10 @@ jobs:
     strategy:
       fail-fast: true
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-node@v2
+    - uses: actions/checkout@v4
+    - uses: actions/setup-node@v4
       with:
-        node-version: '14'
+        node-version: '20'
     - name: Install dependencies (gyp would fail)
       run: npm install || true
     - name: Generate parser sources

.github/workflows/package.yml

@@ -10,10 +10,10 @@ jobs:
     strategy:
       fail-fast: true
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-node@v2
+    - uses: actions/checkout@v4
+    - uses: actions/setup-node@v4
       with:
-        node-version: '14'
+        node-version: '20'
     - name: Install dependencies
       run: npm install
     - name: Regenerate parser sources
@@ -26,10 +26,10 @@ jobs:
     strategy:
       fail-fast: true
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-node@v2
+    - uses: actions/checkout@v4
+    - uses: actions/setup-node@v4
       with:
-        node-version: '14'
+        node-version: '20'
     - name: Install dependencies
       run: npm install
     - name: Run tests