Run always validate post-job

[jneira]

To make mergify not merge prs with failing validate jobs
If a main validate job fails github marks as skipped the rest of workflow jobs.
Otoh mergify considers prs with skipped required jobs as mergeable 😮 🤦

This pr forces the run of the post job, which will fail if any of the previous jobs has failed or skipped

---

Please include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.

Please also shortly describe how you tested your change. Bonus points for added tests!

[andreabedini]

I am confused by Mergify behaviour. Let's hope this fixes it.

[andreasabel]

Before this PR can be merged, the workflow Validate windows-latest ghc-8.10.7 needs to be fixed, to satisfy self-application:

... not merge prs with failing validate jobs

;-)

[Mikolaj]

Looks fine. But I'm confused by the CI failure.

[Mikolaj]

@Mergifyio rebase

[mergify]

rebase

✅ Branch has been successfully rebased

[Mikolaj]

Oh, I see @jneira has spotted the same problem already here: #8120 (comment)

[jneira]

well, I think we have to merge this asap to avoid more bad merges
this change is good precisely cause it makes ci fail
but other prs could add more errors

[jneira]

then we have to tackle the cause of the error, I think the pr bumping versions was

[jneira]

then we have to tackle the cause of the error, I think the pr bumping versions was

we have a succesul run in master after the pr so it probably will not be: https://github.com/haskell/cabal/actions/runs/2268699392

[Mikolaj]

I agree, let's merge. We won't forget to fix the failing tests, because they are failing. Oh, wait, CI passed right now, after a rebase.

???

[Mikolaj]

And here it's now reported good even without a rebase: #8109

[jneira]

yeah, the error has been transient, so maybe due to a bad cache 🤷
in any case this pr will prevent merging prs with failing ci