Use std::optional if available.

Currently, SDK requires C++11 minimum.
So, boost::optional type is used for optional values.
For C++17 and above more convenient is to use std::optional instead.
The task NLAM-23 is about making this type configurable.
This commit is a second part of the task: olp-cpp-sdk-write.

Relates-To: NLAM-23
Signed-off-by: sopov <[email protected]>

Author: asopov-here

olp-cpp-sdk-dataservice-write/src/generated/ConfigApi.h

@@ -51,9 +51,8 @@ class ConfigApi {
    * @param billing_tag An optional free-form tag which is used for grouping
    * billing records together. If supplied, it must be between 4 - 16
    * characters, contain only alpha/numeric ASCII characters  [A-Za-z0-9].
-   * @param callback
-   * @param A callback function to invoke with the catalog configuration
-   * response.
+   * @param callback A callback function to invoke with the catalog
+   * configuration response.
    *
    * @return The cancellation token.
    */