Upgrade Node.js and install Percy

- https://nodejs.org/dist/latest-v20.x
- https://www.browserstack.com/docs/percy/ci-cd/github-actions

.github/workflows/ci.yml

@@ -12,11 +12,13 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: Use Node.js 12.x
-      uses: actions/setup-node@v1
+      uses: actions/setup-node@v3
       with:
-        node-version: 12.x
+        node-version: 20.x
     - name: Install Dependencies
-      run: npm install
+      run: |
+        npm install
+        npm install --global @percy/cli
     - name: Test
       if: success()
       run: make test-ci