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

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I7b2bc0a8b34e4d276c0e8ea2243459aab4e1c177
diff --git a/utility.hpp b/utility.hpp
index f97b505..168bd57 100644
--- a/utility.hpp
+++ b/utility.hpp
@@ -96,7 +96,7 @@
                const T& value)
 {
     using Property = std::string;
-    using Value = sdbusplus::message::variant<T>;
+    using Value = std::variant<T>;
     using PropertyMap = std::map<Property, Value>;
 
     using Interface = std::string;