Provide required username and pass

Author: agilob

modules/openapi-generator/src/main/resources/dart2/api_client.mustache

@@ -7,7 +7,7 @@ class ApiClient {
   {{#authMethods}}
   {{#isBasic}}
   {{#isBasicBasic}}
-    _authentications[r'{{{name}}}'] = HttpBasicAuth();
+    _authentications[r'{{{name}}}'] = HttpBasicAuth('user', 'password');
   {{/isBasicBasic}}
   {{#isBasicBearer}}
     _authentications[r'{{{name}}}'] = HttpBearerAuth();

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api_client.dart

@@ -16,7 +16,7 @@ class ApiClient {
     _authentications[r'api_key'] = ApiKeyAuth('header', 'api_key');
     _authentications[r'api_key_query'] = ApiKeyAuth('query', 'api_key_query');
     _authentications[r'bearer_test'] = HttpBearerAuth();
-    _authentications[r'http_basic_test'] = HttpBasicAuth();
+    _authentications[r'http_basic_test'] = HttpBasicAuth('user', 'password');
     _authentications[r'petstore_auth'] = OAuth();
   }