用composer安装了，但是目前为止还有问题。开发环境是 WAMP PHP5.4.12. 已经打开PHP.ini 的SSL扩展，现在还是提示缺少 curl-ca-bundle.cr
报错
No system CA bundle could be found in any of the the common system locations.
PHP versions earlier than 5.6 are not properly configured to use the system's
CA bundle by default. In order to verify peer certificates, you will need to
supply the path on disk to a certificate bundle to the 'verify' request
option: http://docs.guzzlephp.org/en/latest/clients.html#verify. If you do not
need a specific certificate bundle, then Mozilla provides a commonly used CA
bundle which can be downloaded here (provided by the maintainer of cURL):
https://raw.githubusercontent.com/bagder/ca-bundle/master/ca-bundle.crt. Once
you have a CA bundle available on disk, you can set the 'openssl.cafile' PHP
ini setting to point to the path to the file, allowing you to omit the 'verify'
request option. See http://curl.haxx.se/docs/sslcerts.html for more
information.
根据这个地址 https://github.com/guzzle/RingPHP/blob/master/src/Client/ClientUtils.php 提示是缺少指定的文件
在这个地址 https://raw.githubusercontent.com/bagder/ca-bundle/master/ca-bundle.crt 下载对应的文件 curl-ca-bundle.crt
问题解决