Bump lru from 0.7.8 to 0.8.0 (paritytech#850)

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](jeromefroe/lru-rs@0.7.8...0.8.0)

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

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

client/rpc/Cargo.toml

@@ -16,7 +16,7 @@ evm = { git = "https://github.com/rust-blockchain/evm", rev = "51b8c2ce3104265e1
 futures = "0.3.24"
 hex = "0.4.3"
 log = "0.4.17"
-lru = "0.7.8"
+lru = "0.8.0"
 prometheus = { version = "0.13.1", default-features = false }
 rand = "0.8"
 tokio = { version = "1.19", features = ["sync"] }