feat(kubernetes): Add report flag for summary (#2112)

* feat(k8s): Add report flag for summary
* chore: add headings to the severity columns
* chore: make the default output of k8s summary table

Signed-off-by: Owen Rumney <owen.rumney@aquasec.com>

pkg/commands/app.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/aquasecurity/trivy-db/pkg/metadata"
 	dbTypes "github.com/aquasecurity/trivy-db/pkg/types"
+
 	"github.com/aquasecurity/trivy/pkg/commands/artifact"
 	"github.com/aquasecurity/trivy/pkg/commands/option"
 	"github.com/aquasecurity/trivy/pkg/commands/plugin"
@@ -215,6 +216,12 @@ var (
 		EnvVars: []string{"TRIVY_K8S_NAMESPACE"},
 	}
 
+	reportFlag = cli.StringFlag{
+		Name:  "report",
+		Value: "summary",
+		Usage: "specify a report format for the output. (all,summary default: all)",
+	}
+
 	// TODO: remove this flag after a sufficient deprecation period.
 	lightFlag = cli.BoolFlag{
 		Name:    "light",
@@ -789,6 +796,7 @@ func NewK8sCommand() *cli.Command {
 		Action:  artifact.K8sRun,
 		Flags: []cli.Flag{
 			&namespaceFlag,
+			&reportFlag,
 			&outputFlag,
 			&severityFlag,
 			&exitCodeFlag,