ci: update Nix installation and caching #789

	name: CI

	on:
	push:
	branches:
	- master
	pull_request:
	branches: [master]

	env:
	SLOW_MACHINE: 1

	jobs:
	unit-tests:
	runs-on: ubuntu-latest

	steps:
	- name: Checkout code
	uses: actions/checkout@v3

	- name: Set up Go
	uses: actions/setup-go@v3
	with:
	go-version: 1.18

	- name: Build
	run: make bins

	- name: Test
	run: make test

	integration-tests:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	test-vector: [bitcoin-cln, bitcoin-lnd, liquid-cln, liquid-lnd, misc-integration, lwk-cln, lwk-lnd]
	steps:
	- name: Checkout code
	uses: actions/checkout@v4
	with:
	fetch-depth: 0
	- uses: nixbuild/nix-quick-install-action@v28
	- name: Restore and cache Nix store
	uses: nix-community/cache-nix-action@v5
	with:
	# restore and save a cache using this key
	primary-key: nix-${{ runner.os }}-${{ hashFiles('*/.nix') }}
	# if there's no cache hit, restore a cache by this prefix
	restore-prefixes-first-match: nix-${{ runner.os }}-
	# collect garbage until Nix store size (in bytes) is at most this number
	# before trying to save a new cache
	gc-max-store-size-linux: 1073741824
	# do purge caches
	purge: true
	# purge all versions of the cache
	purge-prefixes: cache-${{ runner.os }}-
	# created more than this number of seconds ago relative to the start of the `Post Restore` phase
	purge-created: 0
	# except the version with the `primary-key`, if it exists
	purge-primary-key: never
	- run: nix-shell --run "make test-${{matrix.test-vector}}"

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