Bump lru from 0.12.5 to 0.16.3 in /aws/rust-runtime

Bumps [lru](https://github.com/jeromefroe/lru-rs) from 0.12.5 to 0.16.3.
- [Changelog](https://github.com/jeromefroe/lru-rs/blob/master/CHANGELOG.md)
- [Commits](jeromefroe/lru-rs@0.12.5...0.16.3)

---
updated-dependencies:
- dependency-name: lru
  dependency-version: 0.16.3
  dependency-type: direct:production
...

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

Author: dependabot[bot]

aws/rust-runtime/Cargo.lock

@@ -35,7 +35,7 @@ http-body = "0.4.5"
 http-1x = { package = "http", version = "1.1.0", optional = true }
 http-body-1x = { package = "http-body", version = "1", optional = true }
 hmac = "0.12"
-lru = "0.12.5"
+lru = "0.16.3"
 ring = "0.17.5"
 sha2 = "0.10"
 tokio = "1.40.0"