Update module github.com/sigstore/fulcio to v1.6.6

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
github.com/sigstore/fulcio	v1.6.4 -> v1.6.6

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Release Notes

sigstore/fulcio (github.com/sigstore/fulcio)

v1.6.6

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Features

• Configure additional certificate extensions for Buildkite (#​1903)
• Relax gomod (#​1909)
• update builder to use go1.23.4 (#​1883)
• config: Add IBM OIDC provider (#​1892)
• Add Kaggle identity provider (#​1850)

Contributors

• Bob Callaway
• Carlos Tadeu Panato Junior
• Hayden B
• James Healy
• Stefan Berger
• Trishank Karthik Kuppusamy

v1.6.5

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Features

• use go1.23.2 (#​1834)
• fallback to json default cfg path if yaml does not exist (#​1810)
• Include IDP type and subject domain in configuration API response (#​1824)

Documentation

• Update OIDC claim mapping table to reflect the current state (#​1801)

Contributors

• Aditya Sirish
• Bob Callaway
• Carlos Tadeu Panato Junior
• Hayden B
• Nina
• Richard Fan

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Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: go.sum

Command failed: go get -d -t ./...
go: module github.com/sigstore/[email protected] requires go >= 1.23.3; switching to go1.23.5
go: downloading go1.23.5 (linux/amd64)
go: download go1.23.5: golang.org/[email protected]: verifying module: checksum database disabled by GOSUMDB=off