Trigger private downstream CI

Github action to trigger workflows using repository dispatch event.

Usage

See action.yml

steps:
  - uses: ecmwf-actions/dispatch-private-downstream-ci@main
    with:
      inputs: ${{ secrets.MY_SECRET_TOKEN }}
      owner: owner
      repository: repo
      event_type: my-custom-event
      payload: '{"input1": "foo"}'

Action creates a repository_dispatch event in target repository. Workflow is specified by event_type. The first step of the first job in target workflow must be the following:

steps:
  - name: ${{ github.event.client_payload.id }}
    run: ...

This is necessary to identify the triggered workflow and to watch for the workflow conclusion.