feat: add the ability to specify the output format when listing ports

plugins/ports/proxy.go

@@ -6,9 +6,9 @@ import (
 
 // PortMap is a struct that contains a scheme:host-port:container-port mapping
 type PortMap struct {
-	ContainerPort int
-	HostPort      int
-	Scheme        string
+	ContainerPort int    `json:"container_port"`
+	HostPort      int    `json:"host_port"`
+	Scheme        string `json:"scheme"`
 }
 
 func (p PortMap) String() string {