Bump tokio from 0.2.10 to 0.2.11

Bumps [tokio](https://github.com/tokio-rs/tokio) from 0.2.10 to 0.2.11.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](https://github.com/tokio-rs/tokio/compare/tokio-0.2.10...tokio-0.2.11)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Cargo.lock

@@ -1321,9 +1321,9 @@ dependencies = [
 
 [[package]]
 name = "tokio"
-version = "0.2.10"
+version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1fc73332507b971a5010664991a441b5ee0de92017f5a0e8b00fd684573045b"
+checksum = "8fdd17989496f49cdc57978c96f0c9fe5e4a58a8bddc6813c449a4624f6a030b"
 dependencies = [
  "bytes",
  "fnv",