Don't rewrite Host in Gateway proxy (#799)

Previously we where rewriting the HTTP `Host` header in the proxy to
preserve the original host information - which would allow Encore to
perform Host based switching behaviour in downstream services.

However this breaks in CloudRun as the load balancers will then end up
rerouting the request back to the proxy - causing an infinite recursion
of calls.

runtime/appruntime/apisdk/api/gateway.go

@@ -36,7 +36,7 @@ func (s *Server) createGatewayHandlerAdapter(h Handler) httprouter.Handle {
 
 	// On cloud environments, we want to log the proxying of requests to services
 	// but locally we don't want the overhead of logging every request.
-	logger := s.rootLogger.With().Str("service", service.Name).Str("endpoint", h.EndpointName()).Logger()
+	logger := s.rootLogger.With().Str("service", service.Name).Str("endpoint", h.EndpointName()).Str("base_url", serviceBaseURL.String()).Logger()
 
 	proxy := s.createProxyToService(service, h.EndpointName(), serviceBaseURL, logger)
 	return func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
@@ -73,7 +73,6 @@ func (s *Server) createProxyToService(service config.Service, endpointName strin
 		// Rewrite the inbound request
 		Rewrite: func(req *httputil.ProxyRequest) {
 			req.SetURL(serviceBaseURL)
-			req.Out.Host = req.In.Host
 
 			t := transport.HTTPRequest(req.Out)
 			t.SetMeta(calleeMetaName, callee) // required by the Handler which verifies we wanted to call this endpoint