chore(deps): Bump lru from 0.17.0 to 0.18.0 (#171)

Bumps [lru](https://github.com/jeromefroe/lru-rs) from 0.17.0 to 0.18.0.
- [Changelog](https://github.com/jeromefroe/lru-rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/jeromefroe/lru-rs/compare/0.17.0...0.18.0)

---
updated-dependencies:
- dependency-name: lru
  dependency-version: 0.18.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

filtermail/Cargo.toml

@@ -25,7 +25,7 @@ governor = { version = "0.10.4", default-features = false, features = [
 ] }
 viadkim = { version = "0.2.0" }
 hickory-resolver = { version = "0.26.1", features = ["dnssec-ring"] }
-lru = "0.17.0"
+lru = "0.18.0"
 parking_lot = "0.12.5"
 tokio-rustls = { version = "0.26.4", default-features = false, features = [
   "ring",