Make sure puppeteer is installed for actions

.github/workflows/run-tests.yml

@@ -22,6 +22,13 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+      - name: Cache node modules
+        uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-${{ hashFiles('**/package.json') }}
+      - name: Install npm dependencies
+        run: npm install
       - name: Copy .env
         run: php -r "file_exists('.env') || copy('.env.github', '.env');"
       - name: Install dependencies