CI succeeds @hsenag

I actually looked at doing this a week or two ago and was a bit put off by haskell-CI/haskell-ci#634 - but if you think it's ok I'm happy to go ahead with it.

@hsenag wrote:

was a bit put off by haskell-CI/haskell-ci#634

haskell-ci is very well maintained, but you have to use the master as it is not frequently released. I update my haskell-ci installation basically every month, to get the latest GHC releases and prereleases.
So if you ask me, yes, I think it is ok.

Atm, there is little choice but to update, because the ubuntu-18.04 virtual environment will be discontinued on 1st April. Yes, that is in 3 days. haskell-ci switched to ubuntu-20.04 in May last year.

• The Ubuntu 18.04 Actions runner image will begin deprecation on 2022/08/08 and will be fully unsupported by 2023/04/03 actions/runner-images#6002
• haskell-CI/haskell-ci@656619d

Final word: I think the problem is not with haskell-ci, but cabal which is badly understaffed while incredibly complex; so bug are introduced. However, if we want to support the latest GHCs, which everyone expects, we also have to live with recent versions of cabal which can talk to the latest GHCs.

haskell-ci is very well maintained, but you have to use the master as it is not frequently released. I update my haskell-ci installation basically every month, to get the latest GHC releases and prereleases.
So if you ask me, yes, I think it is ok.

I was more put off by the fact that the actual maintainer thinks it's broken. But I take your point about the balance of risks :-)