Upgrade to parking_lot 0.11.1

Cargo.toml

@@ -16,7 +16,7 @@ crossbeam-utils = "0.8"
 futures-channel = "0.3.8"
 futures-util = "0.3.8"
 labrpc = { path = "../labrpc" }
-parking_lot = "0.11.0"
+parking_lot = "0.11.1"
 rand = "0.8"
 serde = "1.0.116"
 serde_derive = "1.0.116"