chore: rename master to main (#694)

.github/workflows/ci.yml

@@ -3,7 +3,7 @@ name: CI
 on:
   push:
     branches:
-    - master
+    - main
     tags:
     - '!*'
   pull_request:

readme.md

@@ -1,7 +1,7 @@
 # ncc
 
 [![CI Status](https://github.com/vercel/ncc/workflows/CI/badge.svg)](https://github.com/vercel/ncc/actions?workflow=CI)
-[![codecov](https://codecov.io/gh/vercel/ncc/branch/master/graph/badge.svg)](https://codecov.io/gh/vercel/ncc)
+[![codecov](https://codecov.io/gh/vercel/ncc/branch/main/graph/badge.svg)](https://codecov.io/gh/vercel/ncc)
 
 Simple CLI for compiling a Node.js module into a single file,
 together with all its dependencies, gcc-style.