Add notes regarding make-cargo-build-system #32

	name: test
	on: [push]
	jobs:
	build-with-channels:
	name: Test as Guix channel
	runs-on: ubuntu-latest
	strategy:
	# building independent packages, don’t abort entire build if one fails
	fail-fast: false
	steps:
	- name: Guix cache
	uses: actions/cache@v3
	with:
	path: ~/.cache/guix
	# use a key that (almost) never matches
	key: guix-cache-${{ github.sha }}
	restore-keys: \|
	guix-cache-
	# Cannot use a cache for /gnu/store, since restore fails
	- name: Install Guix
	id: install-guix
	uses: PromyLOPh/guix-install-action@v1
	with:
	channels: \|-
	(list (channel
	(inherit %default-guix-channel))
	(channel
	(name 'rustup)
	(url "https://github.com/declantsien/guix-rustup")
	(introduction
	(make-channel-introduction
	"325d3e2859d482c16da21eb07f2c6ff9c6c72a80"
	(openpgp-fingerprint
	"F695 F39E C625 E081 33B5 759F 0FC6 8703 75EF E2F5")))))
	- name: Build
	run: guix build rust-bin
	- name: Build
	run: guix build -e '((@@ (rustup build toolchain) rustup) "1.78.0")'
	- name: Build
	run: guix build -e '((@@ (rustup build toolchain) rustup) "nightly-2024-05-13")'

Provide feedback