feat(ui): filter doesn't have tooltip (argoproj/argo-cd#4257) (argoproj#63)

Author: jsoref

src/components/top-bar/top-bar.tsx

@@ -39,7 +39,7 @@ export interface TopBarProps extends React.Props<any> {
 const renderFilter = (filter: TopBarFilter<any>) => (
     <DropDown isMenu={true}
             anchor={() => (
-                <div className={classNames('top-bar__filter', { 'top-bar__filter--selected': filter.selectedValues.length > 0 })}>
+                <div className={classNames('top-bar__filter', { 'top-bar__filter--selected': filter.selectedValues.length > 0 })} title='Filter'>
                     <i className='argo-icon-filter' aria-hidden='true'/>
                     <i className='fa fa-angle-down' aria-hidden='true'/>
                 </div>)}>