Update ROADMAP.md

Author: kdinev

ROADMAP.md

@@ -5,7 +5,7 @@
 ## Milestone 9 (Due by September, 2019) 
 
 1. IgxGrid Advanced Filtering [#5496](https://github.com/IgniteUI/igniteui-angular/issues/5496)
-2. IgxGrid row and cell selection modes [#4989](https://github.com/IgniteUI/igniteui-angular/issues/4989)
+2. **[DONE]** IgxGrid row and cell selection modes [#4989](https://github.com/IgniteUI/igniteui-angular/issues/4989)
 3. **[DONE]** Fluent Theme [#5335](https://github.com/IgniteUI/igniteui-angular/issues/5335)
 4. **[DONE]** Drag and Drop enhancements [#5319](https://github.com/IgniteUI/igniteui-angular/issues/5319)
 5. Multi-View Calendar + Range DatePicker [#4282](https://github.com/IgniteUI/igniteui-angular/issues/4282)