Fix build issues with boost 1.87

Update deprecated terminology that was removed in boost 1.87.

Change-Id: I3440a9cec911ed2b40f994733733e408a8fd7551
Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
diff --git a/include/u-boot-env-mgr.hpp b/include/u-boot-env-mgr.hpp
index 4cd0370..b5912f0 100644
--- a/include/u-boot-env-mgr.hpp
+++ b/include/u-boot-env-mgr.hpp
@@ -16,7 +16,7 @@
 
 #pragma once
 
-#include <boost/asio/io_service.hpp>
+#include <boost/asio/io_context.hpp>
 #include <sdbusplus/asio/object_server.hpp>
 
 static constexpr const char* uBootEnvMgrServiceName =
@@ -28,7 +28,7 @@
 
 class UBootEnvMgr
 {
-    boost::asio::io_service& io;
+    boost::asio::io_context& io;
     sdbusplus::asio::object_server& server;
     std::shared_ptr<sdbusplus::asio::connection> conn;
     std::shared_ptr<sdbusplus::asio::dbus_interface> iface;
@@ -37,7 +37,7 @@
     void writeVariable(const std::string& key, const std::string& value);
 
   public:
-    UBootEnvMgr(boost::asio::io_service& io,
+    UBootEnvMgr(boost::asio::io_context& io,
                 sdbusplus::asio::object_server& srv,
                 std::shared_ptr<sdbusplus::asio::connection>& conn);
 };