replace internal module to namespace

sendgrid/sendgrid.d.ts

@@ -3,7 +3,7 @@
 // Definitions by: Maxime LUCE <https://github.com/SomaticIT>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
-declare module Sendgrid {
+declare namespace Sendgrid {
     //#region Options
 
     export interface UriParts {
@@ -166,4 +166,4 @@ declare module Sendgrid {
 declare module "sendgrid" {
     var ctor: Sendgrid.Constructor;
     export = ctor;
-}
+}