Upgrade to Tokio 1.0.0 ecosystem (#530)

* Upgrade Tonic to Tokio 1.0

Work in progress for updating Tonic to Tokio 1.0. Since tower has not
been released to crates.io, a git dependency is taken instead.

* Upgrade Tonic to Tokio 1.0 phase 2

* tonic: remove tower-* deps

* Apply suggestions from code review

Co-authored-by: Ed Marshall <[email protected]>
Co-authored-by: Lucio Franco <[email protected]>

tests/extern_path/my_application/Cargo.toml

@@ -10,8 +10,8 @@ license = "MIT"
 
 [dependencies]
 tonic = { path= "../../../tonic" }
-prost = "0.6"
-prost-types = "0.6"
+prost = "0.7"
+prost-types = "0.7"
 uuid = { package = "uuid1", path= "../uuid" }
 
 [build-dependencies]

tests/extern_path/uuid/Cargo.toml

@@ -9,7 +9,7 @@ license = "MIT"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-prost = "0.6"
-bytes = "0.5"
+prost = "0.7"
+bytes = "1.0"
 [build-dependencies]
-prost-build = "0.6"
+prost-build = "0.7"