Add chair role to knikolla for 2023.2

Only candidate during chair nominations period
https://opendev.org/openstack/governance/src/branch/master/reference/tc-chair-candidates/2023.2

Change-Id: I63eb6c93f5160c6236284d905b78f0d57261f4ce

reference/members.yaml

@@ -38,7 +38,7 @@
   email: knikolla@bu.edu
   memberid: 35202
   date: February 2023
-  role: null
+  role: chair
 
 - name: Brian Rosmaita
   irc: rosmaita
@@ -59,4 +59,4 @@
   email: james.page@ubuntu.com
   memberid: 3097
   date: February 2023
-  role: null
+  role: null