refactor(ci): extract node to own workflow

[miketheman]

To simplify the configuration, extract the node-related steps to their own workflow file.

As the node jobs do not require platform dependencies, service containers like postgres or stripe, we can speed up those steps a little by splitting these apart.

[miketheman]

Timings:

Before, the combined CI workflow "costs" ~26 GitHub Actions minutes

Now with the split, Python ~16 min + Node ~2 min = ~18 minutes, saving 8 minutes of execution time overall

Example runs:
(Python) CI: https://github.com/pypi/warehouse/actions/runs/4246623547/usage
Node CI: https://github.com/pypi/warehouse/actions/runs/4246623544/usage

[ewdurbin]

Nice!

[ewdurbin]

Doing a think on how (if at all) we need to adjust branch protection before/after merge.

[di]

We could merge #12263 which makes it so we don't have to adjust required checks when we add/remove them.

[miketheman]

Doing a think on how (if at all) we need to adjust branch protection before/after merge.

I'm hoping that nothing has to change, since the job names were preserved

[di]

I'm hoping that nothing has to change, since the job names were preserved

Aha, yes this does seem to be the case.

[miketheman]

We could merge #12263 which makes it so we don't have to adjust required checks when we add/remove them.

I forgot about that one - I wonder how it works across multiple workflow files?

[ewdurbin]

We could merge #12263 which makes it so we don't have to adjust required checks when we add/remove them.

I forgot about that one - I wonder how it works across multiple workflow files?

I remember squinting at that and getting confused even before we had multiple workflows.

[miketheman]

hold the phone - I missed something

[miketheman]

Due to a whoopsie, I had removed the actual test command, restored now.

Numbers are still better - https://github.com/pypi/warehouse/actions/runs/4246789167/usage

Python down to ~21 minutes, so 4 minutes savings, not 8.

[webknjaz]

I forgot about that one - I wonder how it works across multiple workflow files?

@miketheman it is possible to make it work through some refactoring, like in this example PR: pypa/build#618.