fix(components/Root): Do not return an element in Root's init

Author: kantord

src/components/root/Root.js

@@ -29,7 +29,7 @@ import { required } from '../../validators'
  */
 const RootComponent = Component({
   'validators': [required('title')],
-  'init': (args, selection) => selection.select('title').text(args.title),
+  'init': (args, selection) => {selection.select('title').text(args.title)},
   'render': (args, selection, data) => {
     const body = selection.select('body')
     body.selectAll('*').remove()

src/manual_test.js

@@ -18,4 +18,7 @@ dashboard "Cereals":
   - 4 columns:
     - attr:query: '.[] | {"component": "rows", "data": [{"component": "text", "args": {"tagName": "h3"}, "data": .name}, {"component": "chart", "args": {"type": "pie"}, "data": {"columns": [["protein", .protein], ["carbo", .carbo], ["sugars", .sugars], ["fat", .fat]]}}]}'
     - data: https://gist.githubusercontent.com/ZeningQu/6184eaf8faa533e320abc938c4738c3e/raw/40f237de825061faa8721c2293b79c46979780b4/cereals.csv
+  - dropdown my_var=foo:
+    - {"value": "foo", "text": "Foo"}
+    - {"value": "bar", "text": "Bar"}
 `)