Updates to close IC Gearing WG

Why is this change being made?

The IC Gearing Working Group has finished. This MR updates the Working Group page and the end date of the working group.

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per [say-why-not-just-what][transparency]
• Assign this change to the correct DRI