Retire add-issue-header.yml workflow

[StanFromIreland]

This was added after the switch to issue templates (see #108033 (comment)), however, it's not ideal. It runs after the issue is opened, and edits the existing issue. This means users can run into conflicts if they edit their issue, it pollutes the edit history, and adds information that is already is available in the form of a label (although this is debatable, as the label is quite a bit smaller).

I propose we remove it, what do people think?

[zware]

Added DNM label to ensure opportunity for discussion so it's not just Stan and I pushing this through in case someone is truly relying on this behavior.

[savannahostrowski]

+1

[webknjaz]

Backport all the way too?

[zware]

Backport all the way too?

IIUC it should be uncontroversial to remove this workflow from all non-main branches regardless of whether it is ultimately removed from main, as it should have no effect in non-default branches. In theory :)

[picnixz]

Yeah this one is annoying. We are already editing the description when a PR is linked (and this causes races sometimes) but I always have edit races with this workflow!

[StanFromIreland]

If I understand correctly, this was originally added as people wanted another way to distinguish issues. To keep the titles that this workflow adds we could alternatively just add them to the issue template, like we have for the docs template:

cpython/.github/ISSUE_TEMPLATE/documentation.yml

Line 13 in a5a4659

label: "Documentation"

This avoids the workflow, and the races, which I think are the most significant issue.

CC @hugovk @AlexWaygood

[hugovk]

It was added to maintain the status quo of the issue templates we used before issue forms.

@StanFromIreland Let's try that, please can you set up a demo in your fork?

[StanFromIreland]

Sure, you can test in https://github.com/StanFromIreland/cpython-ci-testing/issues.

[hugovk]

From the demo: StanFromIreland/cpython-ci-testing#7

This can't maintain the status quo of big obvious title, but it'll do.

[StanFromIreland]

As I see no objections here, and the title has been preserved (albeit as a H3), I'm going merge this now.

[StanFromIreland]

@hugovk, I presume you want to backport for #158399?

[hugovk]

We only need the file deletion and not the template changes, so let's do it as part of #158399.