DOC: more info for dtype argument of get_dummies in whatsnew

Author: Scorpil

doc/source/whatsnew/v0.22.0.txt

@@ -27,6 +27,27 @@ Other Enhancements
 - :class:`pandas.io.formats.style.Styler` now has method ``hide_index()`` to determine whether the index will be rendered in ouptut (:issue:`14194`)
 - :class:`pandas.io.formats.style.Styler` now has method ``hide_columns()`` to determine whether columns will be hidden in output (:issue:`14194`)
 
+``get_dummies`` now supports ``dtype`` argument
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+:func:`get_dummies` function now accepts ``dtype`` argument, which forces specific dtype for new columns. When ``dtype`` is not specified or equals to ``None``, new columns will have dtype ``uint8`` (as before), so this change is backwards compatible. (:issue:`18330`)
+
+**Previous behavior**:
+
+.. ipython:: python
+
+   df = pd.DataFrame({'a': [1, 2], 'b': [3, 4], 'c': [5, 6]})
+   pd.get_dummies(df, columns=['c'])
+
+**New behavior**:
+
+.. ipython:: python
+
+   df = pd.DataFrame({'a': [1, 2], 'b': [3, 4], 'c': [5, 6]})
+   pd.get_dummies(df, columns=['c'])
+   pd.get_dummies(df, columns=['c'], dtype=bool)
+   pd.get_dummies(df, columns=['c'], dtype=np.float64)
+
 .. _whatsnew_0220.api_breaking:
 
 Backwards incompatible API changes