Expose ghcup binary location

[fendor]

Closes #81

Let the bikeshedding commence :)

[andreasabel]

Thanks!

We should verify that the -exe outputs are absolute paths indeed (otherwise we could name it ghcup-exe).

[andreasabel]

• We should check whether the -exe outputs are indeed absolute paths.
• The help text here should not say "path" but something like "The command to invoke ghcup (might not be an absolute path)".

[fendor]

We should check whether the -exe outputs are indeed absolute paths.

Any hints for writing a test? I don't see right away where such a test could be added.

[andreasabel]

Good question!

There is some code in CI that validates the -version outputs of the actions, maybe something similar could be done for the -exe outputs:

setup/.github/workflows/workflow.yml

Lines 166 to 174 in 64f55f9

	- name: Confirm resolved and installed versions match
	shell: bash
	run: |
	CABALVER="$(cabal --numeric-version)"
	GHCVER="$(ghc --numeric-version)"
	echo "CABALVER=${CABALVER}" >> "${GITHUB_ENV}"
	echo "GHCVER=${GHCVER}" >> "${GITHUB_ENV}"
	if [[ "${{ steps.setup.outputs.ghc-version }}" == "latest-nightly" ]]
	then