Modify tokio feature requirement to support bytes empty crate.

Full tokio requires bytes-1.* which is currently only imported has as an empty crate. Alternatively we could import byte-1.1.0 as a non empty crate but that seems to be more dependency than doing this.

Change-Id: I5406c08248655b2a611ccb83015af2f526ff15eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/croscomp/+/3759304
Tested-by: Lucas Berthou <berlu@chromium.org>
Reviewed-by: Andres Calderon Jaramillo <andrescj@google.com>
Reviewed-by: Andres Calderon Jaramillo <andrescj@chromium.org>
Commit-Queue: Lucas Berthou <berlu@chromium.org>
Auto-Submit: Lucas Berthou <berlu@chromium.org>
diff --git a/Cargo.toml b/Cargo.toml
index 7edf5ab..a849d7c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,7 +18,7 @@
 log = "*"
 env_logger = "*"
 structopt = "0.3"
-tokio = { version = "*", features = ["full"] }
+tokio = { version = "*", features = ["macros", "net", "signal", "rt"] }
 tokio-macros = "*"
 jobserver = "*"