Merge pull request #661 from ocefpaf/update_changelog

update changelog

Author: ocefpaf

CHANGES.txt

@@ -1,5 +1,6 @@
 0.4.0
 ~~~~~
+- Added `TimestampedWmsTileLayers` (acrosby #644 and #660)
 - Vega-Lite features support via altair (njwilson23 #643)
 - Experimental support for a static png output (ocefpaf #634)
 - Added support for subdomains options in TileLayer (damselem #623)