docs(changelog): add note about graph fix

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * **Templating**: Fixed issue mixing row repeat and panel repeats, fixes [#4988](https://github.com/grafana/grafana/issues/4988)
 * **Templating**: Fixed issue detecting dependencies in nested variables, fixes [#4987](https://github.com/grafana/grafana/issues/4987), fixes [#4986](https://github.com/grafana/grafana/issues/4986)
+* **Graph**: Fixed broken PNG rendering in graph panel, fixes [#5025](https://github.com/grafana/grafana/issues/5025)
 
 # 3.0.1 Stable (2016-05-11)