yaml_lint action clutters PRs with comments: replace it with pre-commit and a prettier hook

[consideRatio]

We use the https://github.com/karancode/yamllint-github-action, which can be found to comment on PRs.

This is a terrible practice in my mind, and seems to be the default behavior for the action, even though its documented to not be so. Perhaps there a bug that makes the comment happens no matter what?

I suggest this action is dropped in favor of using a pre-commit hook with prettier, that auto-formats the YAML instead of just lints it. I've loved it in z2jh and other projects with big YAML files.

I've just verified also that with prettier, we would catch duplicate keys with a clear error message if they are detected.

prettier.................................................................Failed
- hook id: prettier
- exit code: 2

jupyterhub/Chart.yaml
[error] jupyterhub/Chart.yaml: SyntaxError: Map keys must be unique; "appVersion" is repeated (2:1)
[error]    1 | # Chart.yaml v2 reference: https://helm.sh/docs/topics/charts/#the-chartyaml-file
[error] >  2 | apiVersion: v2
[error]      | ^^^^^^^^^^^^^^
[error] >  3 | name: jupyterhub
[error]      | ^^^^^^^^^^^^^^^^
[error] >  4 | version: 0.0.1-set.by.chartpress
[error]      | ^^^^^^^^^^^^^^^^
[error] >  5 | appVersion: 2.0.0rc2
[error]      | ^^^^^^^^^^^^^^^^
[error] >  6 | appVersion: 2.0.0rc3
[error]      | ^^^^^^^^^^^^^^^^
[error] >  7 | description: Multi-user Jupyter installation
[error]      | ^^^^^^^^^^^^^^^^
[error] >  8 | keywords: [jupyter, jupyterhub, z2jh]
[error]      | ^^^^^^^^^^^^^^^^
[error] >  9 | home: https://z2jh.jupyter.org
[error]      | ^^^^^^^^^^^^^^^^
[error] > 10 | sources: [https://github.com/jupyterhub/zero-to-jupyterhub-k8s]
[error]      | ^^^^^^^^^^^^^^^^
[error] > 11 | icon: https://jupyter.org/assets/hublogo.svg
[error]      | ^^^^^^^^^^^^^^^^
[error] > 12 | kubeVersion: ">=1.17.0-0"
[error]      | ^^^^^^^^^^^^^^^^
[error] > 13 | maintainers:
[error]      | ^^^^^^^^^^^^^^^^
[error] > 14 |   # Since it is a requirement of Artifact Hub to have specific maintainers
[error]      | ^^^^^^^^^^^^^^^^
[error] > 15 |   # listed, we have added some below, but in practice the entire JupyterHub team
[error]      | ^^^^^^^^^^^^^^^^
[error] > 16 |   # contributes to the maintenance of this Helm chart.
[error]      | ^^^^^^^^^^^^^^^^
[error] > 17 |   - name: Erik Sundell
[error]      | ^^^^^^^^^^^^^^^^
[error] > 18 |     email: [email protected]
[error]      | ^^^^^^^^^^^^^^^^
[error] > 19 |   - name: Simon Li
[error]      | ^^^^^^^^^^^^^^^^
[error] > 20 |     url: https://github.com/manics/
[error]      | ^^^^^^^^^^^^^^^^
[error] > 21 |
[error]      | ^

---

To close this

• Add a .pre-commit-config.yaml file, for reference, I suggest looking at for example TLJH's pre-commit config file
  Anything that makes us replace the yaml-lint action is sufficient, this task does not represent adding black and other hooks.
• Remove the yaml_lint action
• I suggest we setup the use of pre-commit.ci to run the pre-commit hook, but an option is to create a dedicated github workflow as well. I've discussed this for example in ci: rely on pre-commit.ci & run tests only if needed jupyterhub/nativeauthenticator#175 (comment) and will refer to that discussion for the motivation.
  If pre-commit.ci is to be used, the 2i2c.org should configure the pre-commit.ci application at https://github.com/organizations/2i2c-org/settings/installations to enable it for this repo.

[consideRatio]

The PR review will show all comments, not just the code surrounding the lines of code changed, but also the code surrounding all comments. This PR was small, but was swamped with comments.

[choldgraf]

this seems pretty reasonable to me - agreed that it is confusing seeing the bot post comments all throughout the file. Does anybody have a strong objection?

[damianavila]

Does anybody have a strong objection?

Nop, in fact, I would be OK-ish with it (btw, I have not used pre-commit.ci before although the concept seems interesting to me).

[choldgraf]

I'm a huge fan of pre-commit.ci