Update go-oidc/v3 to 3.15.0 to address CVE-2025-27144

[jkorany]

https://nvd.nist.gov/vuln/detail/CVE-2025-27144

[jcsf]

We use go-vuln to check for vulnerabilities in cloudflared. In this case, this vulnerability was not flagged, because the way we use go-oidc doesn't exercise it. We will still update the dependency in one of the next releases to avoid false positives.