bmcweb: Remove deprecatd ASIO interfaces

boost::asio::io_service is removed in leiu of io_context, which is a
closer match to the networking TS.  Move us to that implementatio.

This was an automated move using the following command:
git grep -l 'io_service' | xargs sed -i 's/io_service/io_context/g'

Change-Id: I46605521c01f79f86f6901ddf69ddc8c4bc24103
Signed-off-by: Ed Tanous <ed.tanous@intel.com>
diff --git a/src/webserver_main.cpp b/src/webserver_main.cpp
index b4d36ef..7c64f4c 100644
--- a/src/webserver_main.cpp
+++ b/src/webserver_main.cpp
@@ -1,7 +1,7 @@
 #include <crow/app.h>
 #include <systemd/sd-daemon.h>
 
-#include <boost/asio/io_service.hpp>
+#include <boost/asio/io_context.hpp>
 #include <dbus_monitor.hpp>
 #include <dbus_singleton.hpp>
 #include <image_upload.hpp>
@@ -57,7 +57,7 @@
 {
     crow::logger::setLogLevel(crow::LogLevel::DEBUG);
 
-    auto io = std::make_shared<boost::asio::io_service>();
+    auto io = std::make_shared<boost::asio::io_context>();
     CrowApp app(io);
 
 #ifdef BMCWEB_ENABLE_SSL