Update icon for "New private group" menu item

src/images/icons/add-group.svg

-<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
-  <path fill="currentColor" fill-rule="nonzero" d="M8 0c4.42 0 8 3.58 8 8s-3.58 8-8 8-8-3.58-8-8 3.58-8 8-8zm4.645 8.903V7.097a.388.388 0 0 0-.387-.387H9.29V3.742a.388.388 0 0 0-.387-.387H7.097a.388.388 0 0 0-.387.387V6.71H3.742a.388.388 0 0 0-.387.387v1.806c0 .213.174.387.387.387H6.71v2.968c0 .213.174.387.387.387h1.806a.388.388 0 0 0 .387-.387V9.29h2.968a.388.388 0 0 0 .387-.387z"/>
-</svg>
\ No newline at end of file

src/images/icons/add.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16" aria-hidden="true" focusable="false" class="Icon Icon--plus"><g fill-rule="evenodd"><path fill="none" fill-rule="evenodd" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 8V3v5H3h5zm0 0v5-5h5-5z"></path><rect fill="none" stroke="none" x="0" y="0" width="16" height="16"></rect></g></svg>
\ No newline at end of file

src/sidebar/components/group-list-v2.js

@@ -104,7 +104,7 @@ function GroupList({ serviceUrl, settings }) {
 
       {canCreateNewGroup && (
         <MenuItem
-          icon="add-group"
+          icon="add"
           href={newGroupLink}
           label="New private group"
           style="shaded"

src/sidebar/components/svg-icon.js

@@ -6,7 +6,7 @@ const propTypes = require('prop-types');
 
 // The list of supported icons
 const icons = {
-  'add-group': require('../../images/icons/add-group.svg'),
+  add: require('../../images/icons/add.svg'),
   'collapse-menu': require('../../images/icons/collapse-menu.svg'),
   'expand-menu': require('../../images/icons/expand-menu.svg'),
   copy: require('../../images/icons/copy.svg'),