Change update_since to updated_since (#72)

Author: Repin-Daniil

docs/api/api.yaml

@@ -124,7 +124,7 @@ components:
                     items:
                         type: string
                         description: config id
-                update_since:
+                updated_since:
                     type: string
                     format: date-time
                     description: the date from which to watch config updates

src/handlers/configs_values.cpp

@@ -43,7 +43,7 @@ userver::formats::json::Value Handler::
     userver::formats::json::ValueBuilder configs_found{userver::formats::json::MakeObject()};
     for (const auto& config : configs) {
         if (config &&
-            request_data.update_since.value_or(kMinTime).GetTimePoint() <= config->updated_at.GetUnderlying()) {
+            request_data.updated_since.value_or(kMinTime).GetTimePoint() <= config->updated_at.GetUnderlying()) {
             configs_found[config->key.config_name] = config->config_value;
             switch (config->mode) {
                 case uservice_dynconf::models::Mode::kKillSwitchEnabled: