Update Github Actions snippet regarding extension CI

Update actions to latest version. 
Node version updated to a supported one. Could also be 20.x

Author: LucasFA

api/working-with-extensions/continuous-integration.md

@@ -143,11 +143,11 @@ jobs:
     runs-on: $\{{ matrix.os }}
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Install Node.js
-      uses: actions/setup-node@v3
+      uses: actions/setup-node@v4
       with:
-        node-version: 16.x
+        node-version: 18.x
     - run: npm install
     - run: xvfb-run -a npm test
       if: runner.os == 'Linux'