match: add interfacesAdded rule

Change-Id: I1849d54ca395e4cbaccb726118ec35bd0ec0c3ef
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/sdbusplus/bus/match.hpp b/sdbusplus/bus/match.hpp
index 20b0bd7..dc84723 100644
--- a/sdbusplus/bus/match.hpp
+++ b/sdbusplus/bus/match.hpp
@@ -132,6 +132,13 @@
            "member='NameOwnerChanged',"s;
 }
 
+inline auto interfacesAdded()
+{
+    return "type='signal',"
+           "interface='org.freedesktop.DBus.ObjectManager',"
+           "member='InterfacesAdded',"s;
+}
+
 } // namespace rules
 } // namespace match