feat(chips): onRemove callback

equivalent to md-on-remove

Author: Kamil Kisiela

src/types/chips/chips.js

@@ -21,6 +21,9 @@ export default (formlyConfigProvider) => {
         },
         onAdd: {
           bound: 'md-on-add'
+        },
+        onRemove: {
+          bound: 'md-on-remove'
         }
       }
     },
@@ -30,7 +33,8 @@ export default (formlyConfigProvider) => {
         secondaryPlaceholder: check.string.optional,
         deleteButtonLabel: check.string.optional,
         deleteHint: check.string.optional,
-        onAdd: check.func.optional
+        onAdd: check.func.optional,
+        onRemove: check.func.optional
       }
     })
   });