It seems like the plugin doesn't work with the new version of sketch
**Which version of the plugin are you using?**
[ 3.5.0 ] Data Populator for Sketch

**Describe the bug**
Updated my sketch to the latest Version 69 (107357). and the plugin doesn't populate any layers.
the plugin was working just fine on the same symbol prior to update.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'plugin/data populator'
2. Click on 'populate with jason'

**Expected behavior**
to populate my layers

**Environment:**
 - macOS Version: MacOS Mojave 10.14.6
 - Sketch Version Sketch 69
 - Plugin Version 3.5.0
