src/Request.php
public function setSslCaInfo($caInfoFilePath)
    {
        if (is_file($caInfoFilePath)) {
            $this->setSslVerify(2, true);
            $this->curlOptions[ CURLOPT_CAINFO ] = pathinfo($caInfoFilePath, PATHINFO_BASENAME);
            $this->curlOptions[ CURLOPT_CAPATH ] = dirname($caInfoFilePath);
        }

        return $this;
    }
public function setSslCaInfo($caInfoFilePath)
    {
        if (is_file($caInfoFilePath)) {
            $this->setSslVerify(2, true);
            $this->curlOptions[ CURLOPT_CAINFO ] = pathinfo($caInfoFilePath, PATHINFO_BASENAME);
            $this->curlOptions[ CURLOPT_CAPATH ] = dirname($caInfoFilePath);
        }

        return $this;
    }
Request::setSslCaInfo

Sets the name of a file holding one or more certificates to verify the peer with.
It's also set the curl options:
1. CURLOPT_SSL_VERIFYPEER value into TRUE.
2. CURLOPT_SSL_VERIFYHOST value into 2 to check the existence of a common name and also verify that it matches
the hostname provided.
3. CURLOPT_SSL_VERIFYSTATUS value into TRUE to verify the certificate status.

@param string $caInfoFilePath Path to ssl certificate file.

@return static