attributes attachment does not add UATTRIBUTES_VERSION

[matthewd0123]

According to spec, UATTRIBUTES_VERSION of 0x01 should be added to the attachment. Right now, doesn't look like it's getting added.
Found this during interop between zenoh-cpp and zenoh-rust using tck. Attached are logs from the failing test.
CC: @agosh1
attributes_version_error.txt