feat(boards): make droppable area full height

Author: johannesjo

src/app/features/boards/board-task-list/board-task-list.component.scss

@@ -1,6 +1,7 @@
 @import '../../../../variables';
 
 :host {
+  flex-grow: 1;
   display: flex;
   flex-direction: column;
   overflow: auto;