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>