导致该问题的原因在于没有配置curl.cainfo，该配置位于php.ini中。

解决方案：

1）下载cacert.pem

https://curl.haxx.se/ca/cacert.pem

2）配置php.ini

[curl]
; A default value for the CURLOPT_CAINFO option. This is required to be an
; absolute path.
curl.cainfo =E:\phpstudy\PHPTutorial\php\php-7.2.1-nts\cacert.pem

PHP：cURL error 60: SSL certificate unable to get local issuer certificate