Change the type of `cmd` from `String` to `Cmd` #74


	name: format-check

	on:
	push:
	branches:
	- main
	tags: '*'
	pull_request:
	concurrency:
	# Skip intermediate builds: always.
	# Cancel intermediate builds: only if it is a pull request build.
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
	jobs:
	build:
	name: format-check
	runs-on: ${{ matrix.os }}
	strategy:
	fail-fast: false
	matrix:
	version:
	- '1'
	os:
	- ubuntu-latest
	arch:
	- x64
	steps:
	- uses: julia-actions/setup-julia@latest
	with:
	version: ${{ matrix.version }}

	- uses: actions/checkout@v1
	- name: Install JuliaFormatter and format
	# This will use the latest version by default but you can set the version like so:
	#
	# julia -e 'using Pkg; Pkg.add(PackageSpec(name="JuliaFormatter", version="0.13.0"))'
	run: \|
	julia -e 'using Pkg; Pkg.add(PackageSpec(name="JuliaFormatter"))'
	julia -e 'using JuliaFormatter; format(".", verbose=true)'
	- name: Format check
	run: \|
	julia -e '
	out = Cmd(`git diff --name-only`) \|> read \|> String
	if out == ""
	exit(0)
	else
	@error "Some files have not been formatted !!!"
	write(stdout, out)
	exit(1)
	end'

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