Update coverage badge.

Author: dompuiu

README.md

@@ -1,7 +1,7 @@
 # Adobe Experience Platform event forwarding Turbine Edge
 
 [![Build Status](https://img.shields.io/github/actions/workflow/status/adobe/reactor-turbine-edge/node.js.yml?style=flat)](https://github.com/adobe/reactor-turbine-edge/actions)
-[![Coverage Status](https://coveralls.io/repos/github/adobe/reactor-turbine-edge/badge.svg?branch=master)](https://coveralls.io/github/adobe/reactor-turbine-edge?branch=master)
+[![Coverage Status](https://coveralls.io/repos/github/adobe/reactor-turbine-edge/badge.svg?branch=main)](https://coveralls.io/github/adobe/reactor-turbine-edge?branch=main)
 [![npm (scoped with tag)](https://img.shields.io/npm/v/@adobe/reactor-turbine-edge.svg?style=flat)](https://www.npmjs.com/package/@adobe/reactor-turbine-edge)
 
 Adobe Experience Platform event forwarding is a next-generation solution that allows running JavaScript code on Adobe servers.