You can use Slackbot Forwarding Address to get the emails from StockBot app to your Slackbot.
Here are the steps how you can get your Slackbot forwarding address:
From your desktop, click on your profile picture in the top right.
Select Preferences from the menu.
Click on Messages & media.
Scroll down to Bring emails into Slack, then click on Get a forwarding address. Slack will generate a forwarding email address.
Click on Copy
Use the copied forwarding address in StockBot app
Also you can use this address to set up a forwarding rule in your email client, if you like.