message: minifix for r perf regression script
diff: @@ -54,5 +54,5 @@ res <- bench_mark(
  }
  )
  -bench_plot(res, check = TRUE, ref = "master", new = "cpp11", threshold = 0.15)
  +bench_plot(res, check = TRUE, ref = "release", new = "master", threshold = 0.15)
  ggplot2::ggsave("perf_reg.png", width = 9, height = 11)
  