label_in_progress_after_assign.yml

name: Assign and Label In Progress
on:
  issues:
    types:
      - assigned

permissions:
  contents: 'read'
  issues: 'write'

jobs:
  assign_and_label:
    runs-on: ubuntu-latest
    steps:
      - name: Add In Progress label
        uses: actions/github-script@v6
        with:
          script: |
            github.rest.issues.addLabels({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              labels: ['In Progress']
            })