rename master->main

Author: ajpal

README.md

@@ -2,7 +2,7 @@
 
 [![npm version](https://img.shields.io/npm/v/@code-dot-org/maze.svg)](https://www.npmjs.com/package/@code-dot-org/maze)
 [![Travis Build Status](https://img.shields.io/travis/code-dot-org/maze.svg)](https://travis-ci.org/code-dot-org/maze/)
-[![codecov](https://codecov.io/gh/code-dot-org/maze/branch/master/graph/badge.svg)](https://codecov.io/gh/code-dot-org/maze)
+[![codecov](https://codecov.io/gh/code-dot-org/maze/branch/main/graph/badge.svg)](https://codecov.io/gh/code-dot-org/maze)
 
 Standalone repo for the Maze app type
 ### Setup Your Project