Update module github.com/sigstore/fulcio to v1.8.6

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
github.com/sigstore/fulcio	v1.8.5 → v1.8.6

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Release Notes

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

v1.8.6

Compare Source

Features

• Include raw subject in certificates (#​2307)

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[renovate]

ℹ️ Artifact update notice

File name: image/go.mod

In order to perform the update(s) described in the table above, Renovate ran the go get command, which resulted in the following additional change(s):

• 5 additional dependencies were updated
• The go directive was updated for compatibility reasons

Details:

Package	Change
go	1.25.6 -> 1.25.7
github.com/google/go-containerregistry	v0.21.1 -> v0.21.5
github.com/sigstore/protobuf-specs	v0.5.0 -> v0.5.1
google.golang.org/genproto/googleapis/api	v0.0.0-20260401024825-9d38bb4040a9 -> v0.0.0-20260414002931-afd174a4e478
google.golang.org/genproto/googleapis/rpc	v0.0.0-20260401024825-9d38bb4040a9 -> v0.0.0-20260511170946-3700d4141b60
google.golang.org/grpc	v1.80.0 -> v1.81.1