Option to show only title for pulls

[cseas]

Is your feature request related to a problem? Please describe.

The GitHub bot creates a lot of noise by posting the entire pull request description on the Slack notification.

Describe the solution you'd like

There should be an option to configure that we only want the pull request title to show up in the pull request notification to keep the Slack notifications short.

Describe alternatives you've considered

We just disabled the GitHub-Slack integration and resorted to manually posting "please review this" messages.

Additional context N/A