ci: update actions/cache to v4 #1253

	on:
	push:
	branches: [ master ] # Do not run on staging / trying
	pull_request:

	# Checks the crate compiles on nightly rust, and that the logging options for the
	# examples compile on nightly
	name: Nightly rust examples

	jobs:
	ci:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	mcu:
	- stm32h743v
	logging: # Example logging options
	- log-itm
	- log-semihost
	- log-rtt
	env: # Peripheral Feature flags
	FLAGS: rt,xspi,sdmmc,sdmmc-fatfs,fmc,usb_hs,rtc,ethernet,ltdc,crc,rand,can,dsi

	steps:
	- uses: actions/checkout@v4
	- name: Cache cargo registry and index
	uses: actions/cache@v4
	with:
	path: \|
	~/.cargo/registry
	~/.cargo/git
	key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.toml') }}
	- name: Cache cargo build
	uses: actions/cache@v4
	with:
	path: target
	key: ${{ runner.os }}-target-nightly-${{ hashFiles('/Cargo.toml') }}-memory-${{ hashFiles('/memory.x') }}
	- uses: dtolnay/rust-toolchain@nightly
	with:
	targets: thumbv7em-none-eabihf
	- run: cargo build --verbose --release --examples --target thumbv7em-none-eabihf --features ${{ matrix.mcu }},${{ env.FLAGS }},${{ matrix.logging }}
	- run: cargo test --lib --target x86_64-unknown-linux-gnu --features ${{ matrix.mcu }},${{ env.FLAGS }}

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