Argh

`argh_shared`: change serde features to allow `no_std` use #284

	name: Argh

	on: [push, pull_request]

	jobs:
	build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2

	- name: Build
	run: cargo build --workspace --examples --verbose

	- name: Run tests
	run: cargo test --workspace --verbose

	- name: Run simple_example
	run: cargo run --package argh --example simple_example two --fooey

	rustfmt:
	name: rustfmt
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2

	- name: Run Rustfmt
	run: cargo fmt -- --check

	clippy:
	name: clippy
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2

	- name: Run clippy
	run: cargo clippy --version && cargo clippy --tests --workspace -- -D warnings -A clippy::needless-raw-string-hashes

	docs:
	name: docs
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v1

	- name: Check documentation
	env:
	RUSTDOCFLAGS: -D warnings
	run: cargo doc --no-deps --document-private-items --workspace

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