Run gh command on Github Actions as a manual trigger

gh_issue_view.yml

name: gh issue view
on:
  workflow_dispatch: # Manual trigger: https://github.blog/changelog/2020-07-06-github-actions-manual-triggers-with-workflow_dispatch/
    inputs:
      issueNumber:
        description: 'Issue number'

env:
  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

jobs:
  issueView:
    name: View an issue
    runs-on: ubuntu-latest # It includes gh by default: https://github.com/actions/virtual-environments/blob/master/images/linux/Ubuntu2004-README.md
    steps:
    - name: Checkout
      uses: actions/checkout@v2
    - run: gh issue view ${{ github.event.inputs.issueNumber }}