Update http requirement from 0.1 to 0.2

Updates the requirements on [http](https://github.com/hyperium/http) to permit the latest version.
- [Release notes](https://github.com/hyperium/http/releases)
- [Changelog](https://github.com/hyperium/http/blob/master/CHANGELOG.md)
- [Commits](hyperium/http@v0.1.0...v0.2.0)

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

gotham/Cargo.toml

@@ -44,7 +44,7 @@ linked-hash-map = "0.5"
 num_cpus = "1.8"
 regex = "1.0"
 cookie = "0.12"
-http = "0.1"
+http = "0.2"
 httpdate = "0.3"
 failure = "0.1"
 tokio-rustls = {version = "0.9", optional = true }