ci: add node v18 to test workflow (#130)

* ci: add node v18 to test workflow

* ci: use v18.x for github actions

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v3
         with:
-          node-version: '16.x'
+          node-version: '18.x'
       - name: Install dependencies
         run: npm ci
       - name: Lint files
@@ -25,10 +25,10 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        node: [16.x, 14.x, 12.x]
+        node: [18.x, 16.x, 14.x, 12.x]
         include:
         - os: windows-latest
-          node: "16.x"
+          node: "18.x"
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3