Bump directories to 2.0

Author: tesuji

Cargo.toml

@@ -35,7 +35,7 @@ required-features = ["rustc_tests"]
 [dependencies]
 byteorder = { version = "1.1", features = ["i128"]}
 cargo_metadata = { version = "0.8", optional = true }
-directories = { version = "1.0", optional = true }
+directories = { version = "2.0", optional = true }
 rustc_version = { version = "0.2.3", optional = true }
 env_logger = "0.6"
 log = "0.4"