Update parking_lot requirement from 0.11 to 0.12

Updates the requirements on [parking_lot](https://github.com/Amanieu/parking_lot) to permit the latest version.
- [Release notes](https://github.com/Amanieu/parking_lot/releases)
- [Changelog](https://github.com/Amanieu/parking_lot/blob/master/CHANGELOG.md)
- [Commits](Amanieu/parking_lot@0.11.0...0.12.0)

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

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

Cargo.toml

@@ -31,7 +31,7 @@ hex = "0.4"
 futures-executor = "0.3"
 futures-util = "0.3"
 libloading = "0.7"
-parking_lot = "0.11"
+parking_lot = "0.12"
 rand = "0.8"
 reqwest = { version = "0.11", default-features = false, features = [
   "blocking",