chore(deps): update lru requirement from 0.7.5 to 0.12.3

Updates the requirements on [lru](https://github.com/jeromefroe/lru-rs) to permit the latest version.
- [Changelog](https://github.com/jeromefroe/lru-rs/blob/master/CHANGELOG.md)
- [Commits](jeromefroe/lru-rs@0.7.5...0.12.3)

---
updated-dependencies:
- dependency-name: lru
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

sentinel-core/Cargo.toml

@@ -57,7 +57,7 @@ regex = { version = "1.5", optional = true }
 prometheus_exporter = { version = "0.8.4", optional = true }
 # todo: simplify encapsulation
 # using getset = "0.1.1"
-lru = "0.7.5"
+lru = "0.12.3"
 etcd-rs = { version = "0.6", optional = true }
 consul = { version = "0.4", optional = true }
 futures = { version = "0.3.17", optional = true }