zenoh: omit timestamp attachment

This isn't needed for the rmw_zenoh zenohd configuration

src/modules/zenoh/publishers/zenoh_publisher.cpp

@@ -73,8 +73,6 @@ int Zenoh_Publisher::declare_publisher(z_owned_session_t s, const char *keyexpr,
 		return -1;
 	}
 
-	z_timestamp_new(&ts, z_loan(s));
-
 	return 0;
 }
 
@@ -101,9 +99,6 @@ int8_t Zenoh_Publisher::publish(const uint8_t *buf, int size)
 	ze_serializer_finish(z_move(serializer), &attachment);
 	options.attachment = z_move(attachment);
 
-	// Add timestamp
-	options.timestamp = &ts;
-
 	z_owned_bytes_t payload;
 	z_bytes_copy_from_buf(&payload, buf, size);
 	return z_publisher_put(z_loan(_pub), z_move(payload), &options);

src/modules/zenoh/publishers/zenoh_publisher.hpp

@@ -67,7 +67,6 @@ protected:
 
 	z_owned_publisher_t _pub;
 	int64_t sequence_number;
-	z_timestamp_t ts;
 
 	/* 16 bytes DDS-Like GID */
 	uint8_t *rmw_gid;