Add tekton triggers logo 🐈⚽

Adding image from https://github.com/cdfoundation/artwork/tree/master/tekton/additional-artwork/tekton-triggers

Layout is not the greatest, definitely open to some improvements here
(e.g. aligning right or left in the text??)

Author: bobcatfish

README.md

@@ -2,6 +2,10 @@
 
 [![Go Report Card](https://goreportcard.com/badge/tektoncd/triggers)](https://goreportcard.com/report/github.com/tektoncd/triggers)
 
+<p align="center">
+<img src="tekton-triggers.png" alt="Tekton Triggers logo (Tekton cat playing with a ball)"></img>
+</p>
+
 Triggers is a Kubernetes
 [Custom Resource Defintion](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/)
 (CRD) controller that allows you to extract information from events payloads (a