Docs: Add Arm representative to the list of TSC members

Arm is joining OpenBMC Technical Steering Committee.
This patch adds "Supreeth Venkatesh" as Arm representative for the time
being.

Change-Id: I4080e7556f7d1f4c2703eee19245d086ae7935e4
Signed-off-by: Supreeth Venkatesh <supreeth.venkatesh@arm.com>

README.md

@@ -77,3 +77,4 @@ Technical Steering Committee
  * Sai Dasari, Facebook
  * James Mihm, Intel
  * Ali Larijani, Microsoft
+ * Supreeth Venkatesh, Arm