message: added v3.0 migration guide
diff: @@ -244,6 +244,7 @@ New Features
  Please Help Test
  * See tracking issue here: [\#616](https://github.com/gitbrent/PptxGenJS/issue/616)
  +* [Version 3.0 Migration Guide](https://github.com/gitbrent/PptxGenJS/wiki/Version-3.0-Migration-Guide)
  