Support corporate DNS records for Vault Validation

[webmutation]

So this is probably not an easy question...
After reading and testing Using SPIRE and OIDC to Authenticate Workloads to Retrieve Vault Secrets
it works well. However my use case, probably similar to many others, is that our clusters are not exposed to the public network. They do have a DNS entry, usually in our case a nginx RP mapping.

I noticed that on the oidc-discovery-provider.conf its using https://acme-v02.api.letsencrypt.org/directory, would it be possible to replace this with a local option?

Where can I find more details about gcr.io/spiffe-io/oidc-discovery-provider