fix: add helmetData to HelmetProps type

👋 

Since 1.2.0 it is possible to pass an instance of `HelmetData` into `<Helmet>`. It was overlooked to add the `helmetData` prop to the typings.
This PR adds the missing property.

Author: andipaetzold

index.d.ts

@@ -23,6 +23,7 @@ declare module 'react-helmet-async' {
   }
 
   export interface HelmetProps {
+    helmetData?: HelmetData;
     async?: boolean;
     base?: any;
     bodyAttributes?: BodyProps;