cache rustup binary

[prabirshrestha]

setup-rust action takes around 1min even though it is cached. Most likely the rustup binary and few other items are not cached.

setup-rust/src/cargo.ts

Lines 105 to 112 in deec13b

	export function getCachePaths(): string[] {
	return [
	// ~/.cargo/registry
	path.join(CARGO_HOME, 'registry'),
	// /workspace/target/debug
	path.join(WORKSPACE_ROOT, 'target', getCacheTarget()),
	];
	}

Setting cargo environment variables
Adding ~/.cargo/bin to PATH
rustup does not exist, attempting to install
Downloaded installation script to /tmp/rustup-init
[command]/tmp/rustup-init --default-toolchain none -y
info: downloading installer
info: profile set to 'default'
info: default host triple is x86_64-unknown-linux-gnu
info: skipping toolchain installation