[Fixes #72] Fix formatting of `build.rs` #140

	name: Formatting
	on: [push, pull_request]

	env:
	CARGO_TERM_COLOR: always
	MSRV: 1.63.0

	jobs:
	format:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: Specify toolchain
	run: rustup override set $MSRV
	- name: Install Rust (thumbv7em)
	run: rustup target add thumbv7em-none-eabihf
	- name: Install Rustfmt
	run: rustup component add rustfmt
	- run: \|
	set -xeu
	cargo fmt --package atsamx7x-hal -- --check
	for manifest in $(find ./boards -type f -iname Cargo.toml); do
	pushd $(dirname $manifest)
	cargo fmt -- --check
	popd
	done

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