chore: Upgrade to 2021 edition (#808)

tonic-types/Cargo.toml

@@ -1,18 +1,18 @@
 [package]
-name = "tonic-types"
-version = "0.4.0"
 authors = ["Lucio Franco <[email protected]>"]
-edition = "2018"
-license = "MIT"
-documentation = "https://docs.rs/tonic-types/0.4.0/tonic-types/"
-repository = "https://github.com/hyperium/tonic"
-homepage = "https://github.com/hyperium/tonic"
+categories = ["web-programming", "network-programming", "asynchronous"]
 description = """
 A collection of useful protobuf types that can be used with `tonic`.
 """
-readme = "../README.md"
-categories = ["web-programming", "network-programming", "asynchronous"]
+documentation = "https://docs.rs/tonic-types/0.4.0/tonic-types/"
+edition = "2021"
+homepage = "https://github.com/hyperium/tonic"
 keywords = ["rpc", "grpc", "protobuf"]
+license = "MIT"
+name = "tonic-types"
+readme = "../README.md"
+repository = "https://github.com/hyperium/tonic"
+version = "0.4.0"
 
 [dependencies]
 prost = "0.9"