Try to preserve header casing in HTTP/1.1.

Unfortunately, this doesn't actually do anything at the moment due to
what appears to be a bug in hyper.

core/http/Cargo.toml

@@ -43,7 +43,7 @@ cookie = { version = "0.15", features = ["percent-encode"] }
 state = "0.5.1"
 
 [dependencies.hyper]
-version = "0.14.5"
+version = "0.14.9"
 default-features = false
 features = ["http1", "http2", "runtime", "server", "stream"]
 

core/lib/src/server.rs

@@ -421,6 +421,7 @@ impl Rocket<Orbit> {
         let listener = CancellableListener::new(shutdown.clone(), listener, grace, mercy);
         let server = hyper::Server::builder(Incoming::new(listener))
             .http1_keepalive(http1_keepalive)
+            .http1_preserve_header_case(true)
             .http2_keep_alive_interval(http2_keep_alive)
             .serve(hyper::make_service_fn(service_fn))
             .with_graceful_shutdown(shutdown.clone())