CI with private registry and private certs

We are trying to use gitlab CI/CD in our project for which we have deployed our runners and it’s trying to build the docker image in dind. We want to push that image to our own private registry. We have a valid certificate issued from our corporate signing authority and want to use that same certificate.
The pipeline fails

docker tag de-minimis-service docker push
Using default tag: latest
The push refers to repository []
Get x509: certificate signed by unknown authority

Cleaning up file based variables

ERROR: Job failed: exit code 1

Please suggest how are we going to specify that CA for the private registry and eventually for the gitlab-runners