Fix a usage example

README.md

@@ -153,7 +153,7 @@ monitorRamOf pid = do
  Just bud -> do
  let gap = 10 :: Int -- print every 10 sec
  handleNext (Left _) = putStrLn "the process has stopped"
-  handleNext (Right ((mu, _), updated)) = do
+ handleNext (Right ((mu, _), updated)) = do
  putStrLn $ show mu
  go updated
  go x = unfoldMemUsageAfter gap x >>= handleNext