fix(deps): update module github.com/sigstore/sigstore to v1.8.9

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

go.mod

@@ -32,7 +32,7 @@ require (
 	github.com/secure-systems-lab/go-securesystemslib v0.8.0
 	github.com/sigstore/fulcio v1.6.4
 	github.com/sigstore/rekor v1.3.6
-	github.com/sigstore/sigstore v1.8.8
+	github.com/sigstore/sigstore v1.8.9
 	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.9.0
 	github.com/sylabs/sif/v2 v2.19.1

go.sum

@@ -305,8 +305,8 @@ github.com/sigstore/fulcio v1.6.4 h1:d86obfxUAG3Y6CYwOx1pdwCZwKmROB6w6927pKOVIRY
 github.com/sigstore/fulcio v1.6.4/go.mod h1:Y6bn3i3KGhXpaHsAtYP3Z4Np0+VzCo1fLv8Ci6mbPDs=
 github.com/sigstore/rekor v1.3.6 h1:QvpMMJVWAp69a3CHzdrLelqEqpTM3ByQRt5B5Kspbi8=
 github.com/sigstore/rekor v1.3.6/go.mod h1:JDTSNNMdQ/PxdsS49DJkJ+pRJCO/83nbR5p3aZQteXc=
-github.com/sigstore/sigstore v1.8.8 h1:B6ZQPBKK7Z7tO3bjLNnlCMG+H66tO4E/+qAphX8T/hg=
-github.com/sigstore/sigstore v1.8.8/go.mod h1:GW0GgJSCTBJY3fUOuGDHeFWcD++c4G8Y9K015pwcpDI=
+github.com/sigstore/sigstore v1.8.9 h1:NiUZIVWywgYuVTxXmRoTT4O4QAGiTEKup4N1wdxFadk=
+github.com/sigstore/sigstore v1.8.9/go.mod h1:d9ZAbNDs8JJfxJrYmulaTazU3Pwr8uLL9+mii4BNR3w=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=