如果我遵循以下文档： -https://cloud.google.com/community/tutorials/run-symfony-on-appengine-flexible
我的app.yaml如下：
runtime: php
env: flex
runtime_config:
document_root: web
front_controller_file: app.php
env_variables:
APP_ENV: "prod"
但是出现以下错误：
Step #1: Installing dependencies from lock file
Step #1: Your requirements could not be resolved to an installable set of packages.
Step #1:
Step #1: Problem 1
Step #1: - Installation request for league/uri 5.3.0 -> satisfiable by league/uri[5.3.0].
Step #1: - league/uri 5.3.0 requires ext-intl * -> the requested PHP extension intl is missing from your system.
Step #1: Problem 2
Step #1: - Installation request for league/uri-components 1.8.1 -> satisfiable by league/uri-components[1.8.1].
Step #1: - league/uri-components 1.8.1 requires ext-intl * -> the requested PHP extension intl is missing from your system.
Step #1: Problem 3
Step #1: - Installation request for league/uri-hostname-parser 1.1.1 -> satisfiable by league/uri-hostname-parser[1.1.1].
Step #1: - league/uri-hostname-parser 1.1.1 requires ext-intl * -> the requested PHP extension intl is missing from your system.
Step #1: Problem 4
Step #1: - Installation request for league/uri-manipulations 1.5.0 -> satisfiable by league/uri-manipulations[1.5.0].
Step #1: - league/uri-manipulations 1.5.0 requires ext-intl * -> the requested PHP extension intl is missing from your system.
Step #1: Problem 5
Step #1: - Installation request for sylius/sylius v1.2.6 -> satisfiable by sylius/sylius[v1.2.6].
Step #1: - sylius/sylius v1.2.6 requires ext-exif * -> the requested PHP extension exif is missing from your system.
Step #1: Problem 6
Step #1: - sylius/sylius v1.2.6 requires ext-exif * -> the requested PHP extension exif is missing from your system.
Step #1: - stefandoorn/sitemap-plugin v1.0.10 requires sylius/sylius ^1.0 -> satisfiable by sylius/sylius[v1.2.6].
Step #1: - Installation request for stefandoorn/sitemap-plugin v1.0.10 -> satisfiable by stefandoorn/sitemap-plugin[v1.0.10].
Step #1:
Step #1: To enable extensions, verify that they are enabled in your .ini files:
Step #1: - /opt/php72/lib/php-cli.ini
Step #1: - /opt/php72/lib/ext.enabled/ext-apcu-bc.ini
Step #1: - /opt/php72/lib/ext.enabled/ext-mailparse.ini
Step #1: - /opt/php72/lib/ext.enabled/ext-memcached.ini
Step #1: You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
Step #1: The command '/bin/sh -c /build-scripts/composer.sh' returned a non-zero code: 2
Finished Step #1
但是，根据文档：（https://cloud.google.com/appengine/docs/standard/php7/runtime）这些扩展是通过defulat启用的吗？
我已经尝试将php.ini文件添加到我的根文件夹，并将以下内容放入其中：
extension=intl.so
但这没用。