Include action output values - was_dry_run and deleted_branches

[brentwatson]

Description

GitHub actions can take inputs and also provide outputs.

Added some output params so that downstream steps can use the output from this action.

• was_dry_run
• deleted_branches

Example Usage:

jobs:
  delete_old_branches:
    name: Delete old git branches
    runs-on: ubuntu-latest
    steps:
      - name: Run delete-old-branches action
        id: delete_branches
        uses: beatlabs/delete-old-branches-action@v0.0.8
        with:
          repo_token: ${{ github.token }}
          date: '3 months ago'
          dry_run: true

      - name: Slack Notification
        uses: archive/github-actions-slack@v2.4.0
        with:
          slack-bot-user-oauth-access-token: ...
          slack-channel: ...
          slack-text: |
            *The following branches were deleted:*
            ${{steps.delete_branches.outputs.delete_branches}}
            Dry Run?: ${{steps.delete_branches.outputs.was_dry_run}}

More info about output with Docker are in the github docs here: https://docs.github.com/en/actions/creating-actions/creating-a-docker-container-action#creating-an-action-metadata-file

[pkossyfas]

🚀 @brentwatson thanks for this contribution as well!