Update github username for CAPC OWNERS

Author: vishesh92

config/jobs/kubernetes-sigs/cluster-api-provider-cloudstack/OWNERS

@@ -2,7 +2,7 @@
 approvers:
   - davidjumani
   - g-gaston
-  - rohityadavcloud
+  - yadvr
   - chrisdoherty4
   - weizhouapache
   - vishesh92