Switch to `std::sync::LazyLock`

[Serial-ATA]

Usage of once_cell::sync::Lazy was replaced with std::sync::OnceLock awhile ago:

lofty-rs/lofty/src/id3/v2/util/upgrade.rs

Lines 41 to 52 in 1505ddf

	fn v2keys() -> &'static HashMap<&'static str, &'static str> {
	static INSTANCE: OnceLock<HashMap<&'static str, &'static str>> = OnceLock::new();
	INSTANCE.get_or_init(|| {
	let mut map = HashMap::new();
	$(
	$(
	map.insert($v2_key, $id3v24_from_v2);
	)+
	)+
	map
	})
	}

In 1.80.0, std::sync::LazyLock was finally stabilized. Now in that example, we can just go back to using V2_KEYS directly instead of having functions to access it.

This is blocked right now since 1.80.0 just came out and it really isn't that important to do anyway.

[Serial-ATA]

No longer blocked, new MSRV is 1.85