Add Tess as Anne's SG alternate

Author: hober

README.md

@@ -55,7 +55,7 @@ Workstream Participant Agreement which is maintained as
 
 ## Steering Group representatives
 
-* Anne van Kesteren (Apple) [@annevk](https://github.com/annevk)
+* Anne van Kesteren (Apple) [@annevk](https://github.com/annevk) (Alternate: Theresa O’Connor [@hober](https://github.com/hober))
 * Chris Wilson (Google) [@cwilso](https://github.com/cwilso)
 * Diego González (Microsoft) [@diekus](https://github.com/diekus)
 * Tantek Çelik (Mozilla) [@tantek](https://github.com/tantek) (Alternate: Simon Pieters [@zcorpan](https://github.com/zcorpan))