feat: improve toolbar responsiveness for mobile devices (jquense#900)

Author: miltonmc

src/less/toolbar.less

@@ -5,6 +5,8 @@
 
 .rbc-toolbar {
   display: flex;
+  flex-wrap: wrap;
+  justify-content: center;
   align-items: center;
   margin-bottom: 10px;
   font-size: 16px;