Update help text to perform as expected

[troy0820]

What does this change

Changes the help text to properly describe how to use the porter installation run list

List runs of an Installation

Usage:
  porter installations runs list [flags]

Examples:
  porter installations runs list [NAME] [--namespace NAMESPACE] [--output FORMAT]

  porter installations runs list myapp --namespace dev



Flags:
  -h, --help               help for list
  -n, --namespace string   Namespace in which the installation is defined. Defaults to the global namespace.
  -o, --output string      Specify an output format.  Allowed values: plaintext, json, yaml (default "plaintext")

Global Flags:
      --experimental strings   Comma separated list of experimental features to enable. See https://getporter.org/configuration/#experimental-feature-flags for available feature flags.
      --verbosity string       Threshold for printing messages to the console. Available values are: debug, info, warning, error. (default "info")

What issue does it fix

Closes #2514

Notes for the reviewer

Put any questions or notes for the reviewer here.

Checklist

• Did you write tests?
  • No, this just updates the help text
• Did you write documentation?
  • No, there is no documentation update necessary for this change.
• Did you change porter.yaml or a storage document record? Update the corresponding schema file.
• If this is your first pull request, please add your name to the bottom of our Contributors list. Thank you for making Porter better! 🙇‍♀️

Reviewer Checklist

• Comment with /azp run test-porter-release if a magefile or build script was modified
• Comment with /azp run porter-integration if it's a non-trivial PR

[bdegeeter]

lgtm

[schristoff]

/azp run porter-integration

[troy0820]

/azp run porter-integration

[azure-pipelines]

Commenter does not have sufficient privileges for PR 2794 in repo getporter/porter