ci: add Node.js 18 in the test matrix

Reference: https://github.com/nodejs/Release

.github/workflows/ci.yml

@@ -12,18 +12,24 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 16.x]
+        node-version:
+          - 14
+          - 18
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}
 
-      - run: npm ci
+      - name: Install dependencies
+        run: npm ci
 
-      - run: npm test
+      - name: Run tests
+        run: npm test
         env:
           CI: true
         timeout-minutes: 10