Use in-toto CycloneDX predicate to be compatible with cosign (#1270)

Co-authored-by: Christopher Phillips <christopher.phillips@anchore.com>

cmd/syft/cli/attest/attest.go

@@ -359,8 +359,7 @@ func formatPredicateType(format sbom.Format) string {
 	case spdx22json.ID:
 		return in_toto.PredicateSPDX
 	case cyclonedxjson.ID:
-		// Tentative see https://github.com/in-toto/attestation/issues/82
-		return "https://cyclonedx.org/bom"
+		return in_toto.PredicateCycloneDX
 	case syftjson.ID:
 		return "https://syft.dev/bom"
 	default:

cmd/syft/cli/completion.go

@@ -32,7 +32,7 @@ func Completion() *cobra.Command {
 	`,
 		DisableFlagsInUseLine: true,
 		ValidArgs:             []string{"bash", "zsh", "fish"},
-		Args:                  cobra.ExactValidArgs(1),
+		Args:                  cobra.MatchAll(cobra.ExactArgs(1), cobra.OnlyValidArgs),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			var err error
 			switch args[0] {