The feature flag change could push notification to rollout issue

Since we keep track rollout_issue_url:

• We can push as part of ChatOps an automated comment via Bot to the rollout issue once a feature flag is changed.
• We can re-edit description of feature flag rollout to ensure that description always reflects current state of feature flag

This allows us to make developers to perform one-less steps to keep the rollout issue up-to date.