chore: Prepare 0.4 release (#538)

* Prepare `0.4` release

* Fix cargo issues

tonic-types/Cargo.toml

@@ -1,10 +1,10 @@
 [package]
 name = "tonic-types"
-version = "0.1.0"
+version = "0.2.0"
 authors = ["Lucio Franco <[email protected]>"]
 edition = "2018"
 license = "MIT"
-documentation = "https://docs.rs/tonic-types/0.1.0/tonic-types/"
+documentation = "https://docs.rs/tonic-types/0.2.0/tonic-types/"
 repository = "https://github.com/hyperium/tonic"
 homepage = "https://github.com/hyperium/tonic"
 description = """

tonic-types/src/lib.rs

@@ -9,7 +9,7 @@
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/tokio-rs/website/master/public/img/icons/tonic.svg"
 )]
-#![doc(html_root_url = "https://docs.rs/tonic-types/0.1.0")]
+#![doc(html_root_url = "https://docs.rs/tonic-types/0.2.0")]
 #![doc(issue_tracker_base_url = "https://github.com/hyperium/tonic/issues/")]
 
 mod pb {