Upgrade tonic to 0.6 and prost to 0.9

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "etcd-client"
-version = "0.7.3"
+version = "0.8.0"
 authors = ["The etcd-client Authors <[email protected]>"]
 edition = "2018"
 readme = "README.md"
@@ -17,19 +17,19 @@ tls-roots = ["tls", "tonic/tls-roots"]
 pub-response-field = ["visible"]
 
 [dependencies]
-tonic = "0.5.2"
-prost = "0.8.0"
-tokio = "1.11.0"
-tokio-stream = "0.1.7"
+tonic = "0.6.1"
+prost = "0.9.0"
+tokio = "1.14.0"
+tokio-stream = "0.1.8"
 tower-service = "0.3.1"
-http = "0.2.4"
+http = "0.2.5"
 visible =  { version = "0.0.1", optional = true }
 
 [dev-dependencies]
-tokio = { version = "1.11.0", features = ["full"] }
+tokio = { version = "1.14.0", features = ["full"] }
 
 [build-dependencies]
-tonic-build = { version = "0.5.2", default-features = false, features = ["prost"] }
+tonic-build = { version = "0.6.0", default-features = false, features = ["prost"] }
 
 [package.metadata.docs.rs]
 all-features = true