Update cargo to fix deprecation warnings

Implemented in rust-lang/cargo#6600

Author: Mark-Simulacrum

Cargo.lock

@@ -204,15 +204,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cargo"
-version = "0.34.0"
+version = "0.35.0"
 dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "bufstream 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytesize 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "crates-io 0.22.0",
+ "crates-io 0.23.0",
  "crossbeam-utils 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "crypto-hash 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "curl 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -496,7 +496,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "crates-io"
-version = "0.22.0"
+version = "0.23.0"
 dependencies = [
  "curl 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2113,7 +2113,7 @@ dependencies = [
 name = "rls"
 version = "1.31.6"
 dependencies = [
- "cargo 0.34.0",
+ "cargo 0.35.0",
  "cargo_metadata 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "clippy_lints 0.0.212",
  "crossbeam-channel 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",