Use node 18 in coverage

Author: Tyriar

.github/workflows/ci.yml

@@ -78,10 +78,10 @@ jobs:
     timeout-minutes: 10
     steps:
     - uses: actions/checkout@v3
-    - name: Use Node.js ${{ matrix.node-version }}.x
+    - name: Use Node.js 18.x
       uses: actions/setup-node@v3
       with:
-        node-version: ${{ matrix.node-version }}.x
+        node-version: 18.x
         cache: 'yarn'
     - name: Install dependencies
       run: |