Bump tokio from 0.2.21 to 1.6.1

Bumps [tokio](https://github.com/tokio-rs/tokio) from 0.2.21 to 1.6.1.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](tokio-rs/tokio@tokio-0.2.21...tokio-1.6.1)

---
updated-dependencies:
- dependency-name: tokio
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

node/test/service/Cargo.toml

@@ -59,4 +59,4 @@ substrate-test-client = { git = "https://github.com/paritytech/substrate", branc
 pallet-balances = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 serde_json = "1.0.61"
 substrate-test-utils = { git = "https://github.com/paritytech/substrate", branch = "master" }
-tokio = { version = "0.2", features = ["macros"] }
+tokio = { version = "1.6", features = ["macros"] }

parachain/test-parachains/adder/collator/Cargo.toml

@@ -45,4 +45,4 @@ substrate-test-utils = { git = "https://github.com/paritytech/substrate", branch
 sc-service = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 
-tokio = { version = "0.2", features = ["macros"] }
+tokio = { version = "1.6", features = ["macros"] }

utils/staking-miner/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2018"
 
 [dependencies]
 codec = { package = "parity-scale-codec", version = "2.0.0" }
-tokio = { version = "0.2", features = ["macros"] }
+tokio = { version = "1.6", features = ["macros"] }
 log = "0.4.11"
 env_logger = "0.8.3"
 structopt = "0.3.0"