Bump lru from 0.7.8 to 0.8.0 (#6060)

* Bump lru from 0.7.8 to 0.8.0

Bumps [lru](https://github.com/jeromefroe/lru-rs) from 0.7.8 to 0.8.0.
- [Release notes](https://github.com/jeromefroe/lru-rs/releases)
- [Changelog](https://github.com/jeromefroe/lru-rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/jeromefroe/lru-rs/compare/0.7.8...0.8.0)

---
updated-dependencies:
- dependency-name: lru
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Change `LruCache` paramerter to `NonZeroUsize`

* Change type of `session_cache_lru_size` to `NonZeroUsize`

* Add expects instead of unwrap

Co-authored-by: Bastian Köcher <info@kchr.de>

* Use match to get rid of expects

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Sebastian Kunert <skunert49@gmail.com>
Co-authored-by: Bastian Köcher <info@kchr.de>

polkadot/node/core/approval-voting/src/lib.rs

@@ -70,6 +70,7 @@ use std::{
 	collections::{
 		btree_map::Entry as BTMEntry, hash_map::Entry as HMEntry, BTreeMap, HashMap, HashSet,
 	},
+	num::NonZeroUsize,
 	sync::Arc,
 	time::Duration,
 };
@@ -104,7 +105,11 @@ const APPROVAL_CHECKING_TIMEOUT: Duration = Duration::from_secs(120);
 /// Value rather arbitrarily: Should not be hit in practice, it exists to more easily diagnose dead
 /// lock issues for example.
 const WAIT_FOR_SIGS_TIMEOUT: Duration = Duration::from_millis(500);
-const APPROVAL_CACHE_SIZE: usize = 1024;
+const APPROVAL_CACHE_SIZE: NonZeroUsize = match NonZeroUsize::new(1024) {
+	Some(cap) => cap,
+	None => panic!("Approval cache size must be non-zero."),
+};
+
 const TICK_TOO_FAR_IN_FUTURE: Tick = 20; // 10 seconds.
 const APPROVAL_DELAY: Tick = 2;
 const LOG_TARGET: &str = "parachain::approval-voting";