Added missing include

Missing include was causing compilation error when g++-12 was used.

Tested:
- Code compiles

Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
Change-Id: I583c3571dfac5b574d27f2585158d4309681959d
diff --git a/include/sdbusplus/unpack_properties.hpp b/include/sdbusplus/unpack_properties.hpp
index ac681aa..aa63d88 100644
--- a/include/sdbusplus/unpack_properties.hpp
+++ b/include/sdbusplus/unpack_properties.hpp
@@ -10,6 +10,7 @@
 #include <string>
 #include <string_view>
 #include <variant>
+#include <vector>
 
 namespace sdbusplus
 {