Change io_service to io_context

This was renamed a while back in boost to be compliant with the
std::executors proposal.

Change-Id: I221f120fc16d6b9e57eee17417cf7f5793c9629f
Signed-off-by: Ed Tanous <edtanous@google.com>
diff --git a/gpioMon.hpp b/gpioMon.hpp
index b07bb40..51772ab 100644
--- a/gpioMon.hpp
+++ b/gpioMon.hpp
@@ -2,7 +2,7 @@
 
 #include <gpiod.h>
 
-#include <boost/asio/io_service.hpp>
+#include <boost/asio/io_context.hpp>
 #include <boost/asio/posix/stream_descriptor.hpp>
 
 namespace phosphor
@@ -35,7 +35,7 @@
      *  @param[in] continueRun - Whether to continue after event occur
      */
     GpioMonitor(gpiod_line* line, gpiod_line_request_config& config,
-                boost::asio::io_service& io, const std::string& target,
+                boost::asio::io_context& io, const std::string& target,
                 const std::string& lineMsg, bool continueRun) :
         gpioLine(line),
         gpioConfig(config), gpioEventDescriptor(io), target(target),
diff --git a/gpioMonMain.cpp b/gpioMonMain.cpp
index f8084a3..bb30a8e 100644
--- a/gpioMonMain.cpp
+++ b/gpioMonMain.cpp
@@ -17,7 +17,7 @@
 #include "gpioMon.hpp"
 
 #include <CLI/CLI.hpp>
-#include <boost/asio/io_service.hpp>
+#include <boost/asio/io_context.hpp>
 #include <fstream>
 #include <nlohmann/json.hpp>
 #include <phosphor-logging/log.hpp>
@@ -43,7 +43,7 @@
 int main(int argc, char** argv)
 {
 
-    boost::asio::io_service io;
+    boost::asio::io_context io;
 
     CLI::App app{"Monitor GPIO line for requested state change"};