vendor: upgrade containers/storage

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

vendor/github.com/containers/image/copy/sign.go

@@ -0,0 +1,35 @@
+package copy
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/containers/image/signature"
+	"github.com/containers/image/transports"
+	"github.com/containers/image/types"
+	"github.com/pkg/errors"
+)
+
+// createSignature creates a new signature of manifest at (identified by) dest using keyIdentity.
+func createSignature(dest types.ImageDestination, manifest []byte, keyIdentity string, reportWriter io.Writer) ([]byte, error) {
+	mech, err := signature.NewGPGSigningMechanism()
+	if err != nil {
+		return nil, errors.Wrap(err, "Error initializing GPG")
+	}
+	defer mech.Close()
+	if err := mech.SupportsSigning(); err != nil {
+		return nil, errors.Wrap(err, "Signing not supported")
+	}
+
+	dockerReference := dest.Reference().DockerReference()
+	if dockerReference == nil {
+		return nil, errors.Errorf("Cannot determine canonical Docker reference for destination %s", transports.ImageName(dest.Reference()))
+	}
+
+	fmt.Fprintf(reportWriter, "Signing manifest\n")
+	newSig, err := signature.SignDockerManifest(manifest, dockerReference.String(), mech, keyIdentity)
+	if err != nil {
+		return nil, errors.Wrap(err, "Error creating signature")
+	}
+	return newSig, nil
+}