[doc] Update technical committee information

Adding Rupert to list of technical committee members and removing
Alex. Also marking Michael Schaffner as chair.

Signed-off-by: Michael Munday <mike.munday@lowrisc.org>
diff --git a/doc/project/technical_committee.md b/doc/project/technical_committee.md
index 847d994..6566a7f 100644
--- a/doc/project/technical_committee.md
+++ b/doc/project/technical_committee.md
@@ -19,11 +19,11 @@
 
 ## Membership
 The OpenTitan Technical Committee membership is:
-* Alex Bradbury (chair)
+* Michael Schaffner (chair)
 * Richard Bohn
 * Cyril Guyot
 * Felix Miller
 * Dominic Rizzo (observer)
-* Michael Schaffner
 * Alphan Ulusoy
 * Michael Munday
+* Rupert Swarbrick