Remember to change metricsport camelCase on 1.8.4 release

[n1koo]

Describe the bug

#4368 changed camelcase on metricsport to metricsPort which makes sense and is good alignment but as we don't use EnableCaseInsensitive in cobra this will break people using argo-rollouts with Helm - eg see https://github.com/argoproj/argo-helm/blob/main/charts/argo-rollouts/templates/controller/deployment.yaml#L52

Also opened argoproj/argo-helm#3454

To Reproduce

Compile latest master, try to deploy with helm chart

Version

master

Logs

Error: unknown flag: --metricsport
Usage:
  argo-rollouts [flags]