chore: bump github.com/sigstore/sigstore from 1.8.4 to 1.8.7

Bumps [github.com/sigstore/sigstore](https://github.com/sigstore/sigstore) from 1.8.4 to 1.8.7.
- [Release notes](https://github.com/sigstore/sigstore/releases)
- [Commits](sigstore/sigstore@v1.8.4...v1.8.7)

---
updated-dependencies:
- dependency-name: github.com/sigstore/sigstore
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -31,7 +31,7 @@ require (
 	go.step.sm/crypto v0.44.8
 	golang.org/x/sys v0.22.0
 	google.golang.org/api v0.177.0
-	google.golang.org/grpc v1.63.3
+	google.golang.org/grpc v1.64.0
 	gopkg.in/go-jose/go-jose.v2 v2.6.3
 	k8s.io/apimachinery v0.30.3
 )
@@ -63,28 +63,28 @@ require (
 	github.com/buger/jsonparser v1.1.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/cloudflare/circl v1.3.7 // indirect
-	github.com/coreos/go-oidc/v3 v3.10.0 // indirect
+	github.com/coreos/go-oidc/v3 v3.11.0 // indirect
 	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/go-ini/ini v1.67.0 // indirect
-	github.com/go-jose/go-jose/v4 v4.0.1 // indirect
+	github.com/go-jose/go-jose/v4 v4.0.2 // indirect
 	github.com/go-logr/logr v1.4.1 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/google/flatbuffers v2.0.8+incompatible // indirect
-	github.com/google/go-containerregistry v0.19.1 // indirect
+	github.com/google/go-containerregistry v0.20.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/s2a-go v0.1.7 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
 	github.com/googleapis/gax-go/v2 v2.12.3 // indirect
 	github.com/gorilla/mux v1.8.1 // indirect
-	github.com/grpc-ecosystem/grpc-gateway/v2 v2.19.1 // indirect
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.20.0 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/letsencrypt/boulder v0.0.0-20240226214708-a97e074b5a3e // indirect
+	github.com/letsencrypt/boulder v0.0.0-20240620165639-de9c06129bec // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
@@ -107,20 +107,20 @@ require (
 	github.com/wk8/go-ordered-map/v2 v2.1.8 // indirect
 	github.com/zclconf/go-cty v1.14.4 // indirect
 	go.opencensus.io v0.24.0 // indirect
-	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.49.0 // indirect
-	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
-	go.opentelemetry.io/otel v1.26.0 // indirect
-	go.opentelemetry.io/otel/metric v1.26.0 // indirect
-	go.opentelemetry.io/otel/sdk v1.26.0 // indirect
-	go.opentelemetry.io/otel/trace v1.26.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.52.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.52.0 // indirect
+	go.opentelemetry.io/otel v1.27.0 // indirect
+	go.opentelemetry.io/otel/metric v1.27.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.27.0 // indirect
+	go.opentelemetry.io/otel/trace v1.27.0 // indirect
 	go.uber.org/goleak v1.3.0 // indirect
 	golang.org/x/mod v0.17.0 // indirect
-	golang.org/x/oauth2 v0.20.0 // indirect
+	golang.org/x/oauth2 v0.21.0 // indirect
 	golang.org/x/sync v0.7.0 // indirect
 	golang.org/x/time v0.5.0 // indirect
 	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
-	google.golang.org/genproto/googleapis/api v0.0.0-20240429193739-8cf5692501f6 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20240429193739-8cf5692501f6 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20240520151616-dc85e6b867a5 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240520151616-dc85e6b867a5 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	k8s.io/klog/v2 v2.120.1 // indirect
 	k8s.io/utils v0.0.0-20240423183400-0849a56e8f22 // indirect
@@ -145,7 +145,7 @@ require (
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 // indirect
 	github.com/sergi/go-diff v1.3.1 // indirect
-	github.com/sigstore/sigstore v1.8.4
+	github.com/sigstore/sigstore v1.8.7
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect