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/src/u-boot-env-mgr.cpp b/src/u-boot-env-mgr.cpp
index 882e26c..aba8c56 100644
--- a/src/u-boot-env-mgr.cpp
+++ b/src/u-boot-env-mgr.cpp
@@ -57,11 +57,10 @@
     return stdOutput;
 }
 
-UBootEnvMgr::UBootEnvMgr(boost::asio::io_service& io_,
+UBootEnvMgr::UBootEnvMgr(boost::asio::io_context& io_,
                          sdbusplus::asio::object_server& srv_,
                          std::shared_ptr<sdbusplus::asio::connection>& conn_) :
-    io(io_),
-    server(srv_), conn(conn_)
+    io(io_), server(srv_), conn(conn_)
 {
     iface = server.add_interface(uBootEnvMgrPath, uBootEnvMgrIface);
     iface->register_method("ReadAll", [this]() { return readAllVariable(); });