added whatsnew note in the performance section

anmyachev · anmyachev · commit 461776263e9d · 2019-07-03T22:18:28.000+03:00
diff --git a/doc/source/whatsnew/v0.25.0.rst b/doc/source/whatsnew/v0.25.0.rst
@@ -879,6 +879,7 @@ Performance improvements
 - Restored performance of :meth:`DatetimeIndex.__iter__` by re-enabling specialized code path (:issue:`26702`)
 - Improved performance when building :class:`MultiIndex` with at least one :class:`CategoricalIndex` level (:issue:`22044`)
 - Improved performance by removing the need for a garbage collect when checking for ``SettingWithCopyWarning`` (:issue:`27031`)
+- For :meth:`to_datetime` changed default value of cache parameter to ``True`` (:issue:`26043`)
 
 .. _whatsnew_0250.bug_fixes:
 
