Update api_client.mustache

Author: fzyzcjy

modules/swagger-codegen/src/main/resources/dart/api_client.mustache

@@ -105,7 +105,7 @@ class ApiClient {
 
     _updateParamsForAuth(authNames, queryParams, headerParams);
 
-    var ps = queryParams.where((p) => p.value != null).map((p) => '${p.name}=${p.value}');
+    var ps = queryParams.where((p) => p.value != null).map((p) => '${Uri.encodeComponent(p.name)}=${Uri.encodeComponent(p.value)}');
     String queryString = ps.isNotEmpty ?
                          '?' + ps.join('&') :
                          '';