Volunteer as TC liaison for Image Encryption PUT

I already try to keep the Security SIG abreast of what's going on
with the Image Encryption effort and intend to attempt to join the
meetings for the new pop-up team around it, so am happy to act as
their liaison to the TC for as long as I hold a seat there.

Change-Id: Ibc2b3e5c8d26954f0be1c6a86289eb7b0660035a

reference/popup-teams.rst

@@ -32,6 +32,8 @@ Image encryption
 
 * **Co-leads**: Josephine Seifert and Markus Hentsch
 
+* **TC Liaison**: Jeremy Stanley
+
 * **Objective**: Implementing encryption and decryption of images and the
   handling of those images in OpenStack