Split actions into smaller steps

[zegl]

• Baller - Schedule and trigger Codeball Jobs
• Status - Wait for Codeball Result
• Approver - Approve PRs
• Labeler - Label PRs

Status outputs a boolean with the result, and the user can use if-conditions
to trigger the Approver and Labeler actions as desired.

This is a breaking change (to the Approver action), and would only be released
under a new major version.

---

Here's an example of how it can be used:

on: [pull_request]

permissions:
  contents: read
  issues: write
  pull-requests: write

jobs:
  codeball:
    runs-on: ubuntu-latest
    name: Codeball
    steps:
      # Start a new Codeball review job
      # This step is asynchronous and will return a job id
      - name: Trigger Codeball
        id: codeball_baller
        uses: sturdy-dev/codeball-action/baller@labeler

      # Wait for Codeball results, and populate the "approved" output
      - name: Get Status
        id: codeball_status
        uses: sturdy-dev/codeball-action/status@labeler
        with:
          codeball-job-id: ${{ steps.codeball_baller.outputs.codeball-job-id }}

      # The following actions are fully customisable by the user, to create any desired workflow

      - name: Label Approved
        uses: sturdy-dev/codeball-action/labeler@labeler
        if: ${{ steps.codeball_status.outputs.approved == 'true' }}
        with:
          name: "codeball:approved"
          color: "86efac" # green

      - name: Label Needs Review
        uses: sturdy-dev/codeball-action/labeler@labeler
        if: ${{ steps.codeball_status.outputs.approved == 'false' }}
        with:
          name: "codeball:needs-review"
          color: "bfdbfe" # blue

      - name: Approve PR
        uses: sturdy-dev/codeball-action/approver@labeler
        if: ${{ steps.codeball_status.outputs.approved == 'true' }}

[krlvi]

Looks reasonable to me. The only comment i have is lets use "needs review" or "needs human review" instead of the term rejection, since we target a high precision at the cost of lower recall.