Update Node.js version to 18

Author: Elodie0530

.github/workflows/main.yml

@@ -53,7 +53,7 @@ jobs:
       - name: Set up npm
         uses: actions/setup-node@v3
         with:
-          node-version: 16
+          node-version: 18
 
       - name: Install caprover
         run: npm install -g caprover