Refactor PR CI #4

	# Since Rust 1.72+ MIPS is a Tier 3 platform, and there are many errors on the latest nightly to use -Z build-std.
	# So we pin it to 1.71 to produce valid targets
	# Ref: https://github.com/rust-lang/compiler-team/issues/648

	on: [push, pull_request]

	name: Cross-compile MIPS

	jobs:
	build:
	name: Build
	runs-on: ubuntu-latest
	strategy:
	matrix:
	target:
	- mips-unknown-linux-musl
	steps:
	- uses: actions/checkout@v2
	- uses: actions-rs/toolchain@v1
	with:
	toolchain: 1.71
	target: ${{ matrix.target }}
	override: true
	- uses: actions-rs/cargo@v1
	with:
	use-cross: true
	command: build
	args: --target=${{ matrix.target }} --examples

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