Add portName to the PortEvent payload of the event api

[etanshaul]

fixes #1798

Adds in the portName mainly so that clients can distinguish "normal" application port forwards from debug ports.

[etanshaul]

Hmm for some reason I'm not getting portName back even after these changes:

event {
  portEvent {
    localPort: 5005
    remotePort: 5005
    podName: "skaffold-spring-boot-5c4d6b7c94-s6ft8"
    containerName: "skaffold-spring-boot"
    namespace: "default"
  }
}

Investigating..

[etanshaul]

oops my fault. forgot to regenerate the client code from the proto on the other end :)

[etanshaul]

ready for review. sample output from event api PortEvent:

event {
  portEvent {
    localPort: 5005
    remotePort: 5005
    podName: "skaffold-spring-boot-5c4d6b7c94-k7qq9"
    containerName: "skaffold-spring-boot"
    namespace: "default"
    portName: "debug"
  }
}