Check the hash of (downloaded) ninja binary before executing

[jmackie]

If we're going to download and execute ninja, we should really check its integrity.

ditto/crates/ditto-cli/src/ninja.rs

Lines 28 to 36 in e0401de

	pub async fn run(matches: &ArgMatches) -> Result<()> {
	let exe = get_ninja_exe().await?;
	let args = matches.get_many::<String>("ninja_args").unwrap();
	let status = process::Command::new(exe)
	.args(args)
	.status()
	.into_diagnostic()?;
	process::exit(status.code().unwrap_or(0));
	}