Better documentation and error handling of missing permission to create PRs

[dreua]

First of all thanks for the action! It worked well for me in my test-setup but after adding it to another repo it failed, that's why we're here:

I got these errors until I figured out that I needed to change the settings of my repository. It would have been nice to have a hint in the Readme (did I not see it?) and ideally directly in the error message hinting at what needs to be configured.

Run gr2m/create-or-update-pull-request-action@v1.x
Branch "create-or-update-pull-request-action" does not yet exist on remote.
Error: Command failed with exit code 128 (Unknown system error -128): git push -f ***github.com/dreua/flatpak-module-qpdf-pikepdf.git HEAD:refs/heads/create-or-update-pull-request-action
    at makeError (/home/runner/work/_actions/gr2m/create-or-update-pull-request-action/v1.x/dist/index.js:7699:11)
    at handlePromise (/home/runner/work/_actions/gr2m/create-or-update-pull-request-action/v1.x/dist/index.js:10615:26)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async runShellCommand (/home/runner/work/_actions/gr2m/create-or-update-pull-request-action/v1.x/dist/index.js:997:32)
    at async main (/home/runner/work/_actions/gr2m/create-or-update-pull-request-action/v1.x/dist/index.js:758:5) {
  command: 'git push -f ***github.com/dreua/flatpak-module-qpdf-pikepdf.git HEAD:refs/heads/create-or-update-pull-request-action',
  exitCode: 128,
  exitCodeName: 'Unknown system error -128',
  stdout: '',
  stderr: 'remote: Permission to dreua/flatpak-module-qpdf-pikepdf.git denied to github-actions[bot].\n' +
    "fatal: unable to access 'https://github.com/dreua/flatpak-module-qpdf-pikepdf.git/': The requested URL returned error: 403",
  all: 'remote: Permission to dreua/flatpak-module-qpdf-pikepdf.git denied to github-actions[bot].\n' +
    "fatal: unable to access 'https://github.com/dreua/flatpak-module-qpdf-pikepdf.git/': The requested URL returned error: 403",
  failed: true,
  timedOut: false,
  isCanceled: false,
  killed: false,
  signal: undefined

Note that the tick in "Allow GitHub Actions to create and approve pull requests" is not sufficient, you need the "Read and write permissions" setting. Whether the checkbox needs to be ticket at all needs to be tested, I'm just happy that it works now.

[gr2m]

ohhh that is new! Yes, if you could send a pull request to document it, that'd be much apprecaited

[dreua]

Actually I didn't offer to make a PR and already spent more time on this then I intended to. If someone else could take care of it, that would be much appreciated, my open source plate is already quite full.