OIDC URL is ignored in SigningConfig

[haydentherapper]

Description

Version

Specified the following SigningConfig in a ClientTrustConfig:

  "signingConfig": {
    "ca_url": "https://fulcio.sigstage.dev",
    "oidc_url": "https://oauth2.sigstage.dev/auth",
    "tlog_urls": [
      "https://rekor.sigstage.dev"
    ],
    "tsa_urls": [
      "https://timestamp.sigstage.dev/api/v1/timestamp"
    ]
  }

The OIDC URL was ignored, and defaulted to prod. To work around this, I provided an identity token obtained out of band.

[jku]

Should get fixed in #1363