Fix momentjs import, closes #1901, closes #1859

Author: Rico Suter

src/NSwag.CodeGeneration.TypeScript/Templates/File.liquid

@@ -60,7 +60,7 @@ import * as jQuery from 'jquery';
 {%-    endif -%}
 {%-    if Framework.UseMomentJS -%}
 
-import * as moment from 'moment';
+import moment from 'moment';
 {%-        if RequiresMomentJSDuration -%}
 import 'moment-duration-format';
 {%-        endif -%}