Add Changelog entry for new runner configuration

CHANGELOG

@@ -6,6 +6,7 @@ v 8.8.0 (unreleased)
   - Assign labels and milestone to target project when moving issue. !3934 (Long Nguyen)
   - Use a case-insensitive comparison in sanitizing URI schemes
   - Toggle sign-up confirmation emails in application settings
+  - Make it possible to prevent tagged runner from picking untagged jobs
   - Project#open_branches has been cleaned up and no longer loads entire records into memory.
   - Escape HTML in commit titles in system note messages
   - Improve multiple branch push performance by memoizing permission checking