Update README.md

Author: machow

README.md

@@ -55,7 +55,7 @@ board.pin_write(mtcars.head(), "mtcars", type="csv")
 
 Above, we saved the data as a CSV, but depending on
 what you’re saving and who else you want to read it, you might use the
-`type` argument to instead save it as a `joblib` or `arrow` file (NOTE: arrow is not yet supported).
+`type` argument to instead save it as a `joblib` or `arrow` file.
 
 You can later retrieve the pinned data with `.pin_read()`: