Update examples to start mysql service

examples/yii2-mysql.yml

@@ -38,6 +38,8 @@ jobs:
           php-version: ${{ matrix.php-versions }}
           extensions: mbstring, intl, gd, imagick, zip, dom, mysql
           coverage: xdebug #optional
+      - name: Start mysql service
+        run: sudo /etc/init.d/mysql start
       - name: Get composer cache directory
         id: composer-cache
         run: echo "::set-output name=dir::$(composer config cache-files-dir)"