sdbusplus: replace message::variant with std::variant

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I4caefe2492f88886ed485204fc347b71efa4bc5e
diff --git a/item_updater.cpp b/item_updater.cpp
index 32e046c..141150f 100644
--- a/item_updater.cpp
+++ b/item_updater.cpp
@@ -237,7 +237,7 @@
                                       SYSTEMD_PROPERTY_INTERFACE, "Get");
     method.append(CHASSIS_STATE_OBJ, "CurrentPowerState");
 
-    sdbusplus::message::variant<std::string> currentChassisState;
+    std::variant<std::string> currentChassisState;
 
     try
     {