I emailed back and forth with Jacob and we figured out the problem but I thought that I would include it here in case anyone searches.
The problem occurred because cURL was unable to verify the certificate provided by the server. This can be solved in two different ways:
1. Use curl with CURLOPT_SSL_VERIFYPEER => false which allows curl to make insecure connections, that is curl does not verify the certificate.
2. Add the root CA (the CA signing the server certificate) to etc/ssl/certs/ca-certificates.crt
I will do an update later today that allows for an option to allow insecure connections if the user needs to do that. The default cURL calls in both the GitHub Readme and GitHub File Contents shortcodes will still be secure.
If you do need to use insecure connection then use the following syntax (this is an example using Font Awesome): [embedGitHubReadme owner=”FortAwesome” repo=”Font-Awesome” insecure=“true”]