docs: trivy k8s new experiance

Signed-off-by: chenk <[email protected]>

docs/docs/target/kubernetes.md

@@ -30,6 +30,12 @@ Kubernetes resource definition is scanned for:
 
 Trivy follows the behavior of the `kubectl` tool as much as possible.
 
+```sh
+trivy k8s [flags] [CONTEXT] -  if the target name [CONTEXT] is not specified, the default will be used.
+```
+
+for example:
+
 ```sh
 trivy k8s --report summary
 ```