TLS verification on OIDC Issuers

[dandresm]

Right now a typical OIDC Issuer config would look like this:

"https://keycloak.local/sigstore-realm": { "IssuerURL": "https://key cloak.local/sigstore-realm", "ClientID": "sigstore", "Type": "email" }

In our use case, using an internal OIDC provider causes x509 certificate verification failure, because the TLS certificate is signed by an internal CA. My proposal is adding an optional parameter (TlsVerify=false) for disabling TLS verification when interacting with some OIDC providers. It would be even better to pass the certificate as parameter in PEM format, so fulcio can trust this certificate.

[haydentherapper]

Feel free to submit a PR for this! I would recommend adding it as a configuration for an OIDC issuer.

[Sifungurux]

@dandresm are you working on this :)