Add @sbswg as an owner 😼

Scott has been provided super detailed helpful reviews for a while now
(58 reviews as of
https://tekton.devstats.cd.foundation/d/46/pr-reviews-by-contributor?orgId=1&var-period=d&var-repo_name=tektoncd%2Fpipeline&var-reviewers="sbwsg").

He has contributed useful and technically challenging features such as
#905 (recreate pods in face of
ResourceQuota errors), drove completion of
#936
(Graceful sidecar support) and also #871
(enforcing default TaskRun timeouts).

OWNERS

@@ -8,6 +8,7 @@ approvers:
 - abayer
 - afrittoli
 - dibyom
+- sbwsg
 
 # Alumni ❤️
 # tejal29