Change io_service to io_context

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

Change-Id: Ic563e4e78b3c814037090606c51638868557327e
Signed-off-by: Ed Tanous <edtanous@google.com>
diff --git a/include/error_monitors.hpp b/include/error_monitors.hpp
index 55b8790..80332b0 100644
--- a/include/error_monitors.hpp
+++ b/include/error_monitors.hpp
@@ -36,7 +36,7 @@
 }
 
 // Start the signal monitors
-bool startMonitors(boost::asio::io_service& io,
+bool startMonitors(boost::asio::io_context& io,
                    std::shared_ptr<sdbusplus::asio::connection> conn)
 {
     // smiMonitor =