oc-mirror in a disconnected environment fails with error "x509: certificate signed by unknown authority"

Issue

• "oc-mirror" references the host's system Certificate Keyring. It's inconvenient that a system-wide certificate must be installed since in typical cases users don't have the privilege of such operations
• Trying to use "oc-mirror" against a private registry with custom CA certificate returns x509: certificate signed by unknown authority
• I am running as a rootless user on my environment and can't run update-ca-trust commands like shown in How to install a CA certificate on Red Hat Enterprise Linux 7 and later?