Add @wlynch as an OWNER ⚡

@wlynch has been active on the Triggers project for a while now adding a bunch of
features - multiple bindings, interceptors, ongoing work on go modules etc. He has
also reviewed 42 PRs and meets the OWNERS requirements!
https://tekton.devstats.cd.foundation/d/46/pr-reviews-by-contributor?orgId=1&from=1563041702101&to=1578942902101&var-period=q&var-repo_name=tektoncd%2Ftriggers&var-reviewers=%22wlynch%22

OWNERS

@@ -7,3 +7,4 @@ approvers:
 - iancoffey
 - ncskier
 - vtereso
+- wlynch