fix some spelling mistakes in ./data/announcements/scheduled.yaml
Signed-off-by: Celeste Horgan <celeste@cncf.io>
This change allows announcements to have an expiry date and / or a “do not show until” date. Separating this out also leaves room for future changes to enforce a set of approvers. Co-Authored-By: Karen Bradshaw <kbhawkey@gmail.com>