haskell-actions/setup, could we use it?

[philderbeast]

Could we use haskell-actions/setup in our github workflows?

It’s sad that we have to add so much boilerplate for such a simple step.
Is this ghcup cache thing still relevant? I think using haskell-actions/setup
is cleaner: could we use it?

Originally posted by @ulysses4ever in #9573 (comment)

[philderbeast]

The repetition we have:

$ grep -rwn --exclude-dir=".git" --include="*.yml" . -e 'sudo mkdir -p /usr/local/.ghcup/cache'
./.github/workflows/changelogs.yml:40:            sudo mkdir -p /usr/local/.ghcup/cache
./.github/workflows/validate.yml:266:            sudo mkdir -p /usr/local/.ghcup/cache
./.github/workflows/quick-jobs.yml:36:            sudo mkdir -p /usr/local/.ghcup/cache
./.github/workflows/quick-jobs.yml:77:            sudo mkdir -p /usr/local/.ghcup/cache
./.github/workflows/quick-jobs.yml:111:            sudo mkdir -p /usr/local/.ghcup/cache
./.github/workflows/bootstrap.yml:54:            sudo mkdir -p /usr/local/.ghcup/cache

cabal/.github/workflows/quick-jobs.yml

Lines 32 to 40 in ef8ab97

	- name: Sudo chmod to permit ghcup to update its cache
	run: |
	if [[ "${{ runner.os }}" == "Linux" ]]; then
	sudo ls -lah /usr/local/.ghcup/cache
	sudo mkdir -p /usr/local/.ghcup/cache
	sudo ls -lah /usr/local/.ghcup/cache
	sudo chown -R $USER /usr/local/.ghcup
	sudo chmod -R 777 /usr/local/.ghcup
	fi

[ulysses4ever]

The main workflow, Validate, is already using the action happily, so I do think it's impossible…