bmcweb: Replace deprecated boost call

The boost::asio::io_context::post() is deprecated and will not build
when boost library is version 1.71.0.

See CMakeLists.txt
271 if ("${Boost_VERSION}" STREQUAL "107100")
272     add_definitions (-DBOOST_ASIO_NO_DEPRECATED)
273 endif ()

Signed-off-by: Zhenfei Tai <ztai@google.com>
Change-Id: Iacd657af320ba6eebb1518cd86a955f355ed5068
diff --git a/redfish-core/lib/task.hpp b/redfish-core/lib/task.hpp
index fa072a7..2f86a6a 100644
--- a/redfish-core/lib/task.hpp
+++ b/redfish-core/lib/task.hpp
@@ -17,6 +17,7 @@
 
 #include "node.hpp"
 
+#include <boost/asio.hpp>
 #include <boost/container/flat_map.hpp>
 #include <chrono>
 #include <variant>
@@ -182,7 +183,8 @@
                     self->finishTask();
 
                     // reset the match after the callback was successful
-                    crow::connections::systemBus->get_io_context().post(
+                    boost::asio::post(
+                        crow::connections::systemBus->get_io_context(),
                         [self] { self->match.reset(); });
                     return;
                 }