Use v4 UUID instead of v1 for action IDs

This uses a purely random v4 UUID instead of a time-based v1 UUID for
the action IDs (which were introduced in storybookjs#1347).

v1 UUID are based on current time and the hardware MAC address of the
machine where they are being generated (although the implementation in
the npm uuid module uses generates a random fake MAC address). As such
they have much more complex semantics than v4 UUIDs which are simply
randomly generated.

Unless there's a specific requirement for the special semantics of v1
UUIDs it is simpler and less error prone to simply go for v4 UUIDs
whenever just a unique identifier is needed.

addons/actions/src/preview/action.ts

@@ -1,4 +1,4 @@
-import uuid from 'uuid/v1';
+import uuid from 'uuid/v4';
 import { addons } from '@storybook/addons';
 import { EVENT_ID } from '../constants';
 import { ActionDisplay, ActionOptions, HandlerFunction } from '../models';