npuzone: use buildomat for determining versions of things

[rcgoodfellow]

replace this

softnpu/src/bin/npuzone.rs

Lines 157 to 185 in dbab082

	async fn fetch_head_softnpu_commit(branch: &str) -> anyhow::Result<String> {
	Ok(octocrab::instance()
	.repos("oxidecomputer", "softnpu")
	.list_commits()
	.branch(branch)
	.page(1u32)
	.per_page(1)
	.send()
	.await?
	.take_items()[0]
	.sha
	.clone())
	}
	async fn fetch_head_sidecar_lite_commit(
	branch: &str,
	) -> anyhow::Result<String> {
	Ok(octocrab::instance()
	.repos("oxidecomputer", "sidecar-lite")
	.list_commits()
	.branch(branch)
	.page(1u32)
	.per_page(1)
	.send()
	.await?
	.take_items()[0]
	.sha
	.clone())
	}

with calls to buildomat to avoid rate limiting