Support local actions defined in repository

[paul-sachs]

Is your feature request related to a problem? Please describe.
I have a few locally created actions in the .github/actions directory but validation and autocomplete don't seem to work on these actions.

I have the following yaml file at .github/actions/wait-for-deployment-action

name: Wait for deployment
description: |
  Block until a deployment is finished for the pushed commit,
  and get the URL for running any further tests.
branding:
  icon: clock
  color: black

inputs:
  github-token:
    description: Your GitHub access token
    required: true
  environment:
    description: The deployment environment to wait for
  timeout:
    description: The number of seconds after which to fail if no deployment is found.
    default: 30
  interval:
    description: The number of seconds to wait between repeated checks for deployments.
    default: 5
  sha:
    description: |
      The commit SHA to wait for. Defaults to the current commit SHA. For PRs, this is the merge commit SHA.
      So provide ${{ github.event.pull_request.head.sha }} instead.

outputs:
  url:
    description: The deployment URL
  id:
    description: The GitHub deployment id

runs:
  using: node16
  main: dist/index.js

The below shows an attempt to autocomplete the params expected by a local action:

Describe the solution you'd like
For local actions to be validated and provide autocomplete for locally defined actions.