What is your host operating system? Are you behind a VPN, proxy or in a company network? If you installed ca-certificates and you still get this error the reason could be something in your network. It is not about the centos repo, but the Docker Hub, so the ini file is not relevant here.
I reformatted your post, please, use code blocks for sharing code as described in the below topic:
So your host is Centos not just the Docker image. Well, it looks like ca-certificates does not exist on centos. I don’t use centos so I am not sure what the alternative is if it is required at all. You still haven’t replied my other questions.