serialize_log: Use utf-8 encoding for files
serialize_log: Use utf-8 encoding for files

ldtri0209/robotframework,ldtri0209/robotframework,fiuba08/robotframework,fiuba08/robotframework,fiuba08/robotframework,ldtri0209/robotframework,ldtri0209/robotframework,waldenner/robotframework,waldenner/robotframework,fiuba08/robotframework,waldenner/robotframework,waldenner/robotframework,ldtri0209/robotframework,waldenner/robotframework,fiuba08/robotframework