Update Cargo in the RLS

Fixes the fallout of rust-lang/rust#54334

Author: alexcrichton

Cargo.lock

@@ -11,7 +11,7 @@ categories = ["development-tools"]
 build = "build.rs"
 
 [dependencies]
-cargo = { git = "https://github.com/rust-lang/cargo", rev = "9311f6d439e09da3ab918397a425be57da13f04a" }
+cargo = { git = "https://github.com/rust-lang/cargo", rev = "04cec5fc10a7bbe1dccaad5729eff1823ef2608c" }
 cargo_metadata = "0.6"
 clippy_lints = { git = "https://github.com/rust-lang-nursery/rust-clippy", rev = "183639b70bacf457920694d78a19cefe3565e1c0", optional = true }
 env_logger = "0.5"