Note: disabling SSL verification has security implications. It allows Man in the Middle attacks when you use Git to transfer data over a network. Be sure you fully understand the security implications before using this as a solution. Or better yet, install the root certificates.
One way is to disable the SSL CERT verification:
git config --global http.sslVerify false
This will prevent CURL to verity the HTTPS certification.
For one repository only:
git config http.sslVerify false
https://stackoverflow.com/questions/3777075/ssl-certificate-rejected-trying-to-access-github-over-https-behind-firewall