External TLS cert for acme-proxy

I am interested in using acme-proxy to centralize/secure the EAB credentials needed to get commercial certificates from Digicert. However I'd prefer that acme-proxy not use Digicert for it's own certificate. It would be really nice if we could provide our own cert/key for acme-proxy to us. Would it be possible to allow users to optionally specify a path to an existing certificate/key, rather than assume that acme-proxy is responsible for managing it's own cert?