chore: replace instances of master with main [skip ci]

.github/workflows/ci.yml

@@ -2,9 +2,9 @@ name: Node.js CI
 
 on:
   push:
-    branches: [ master, main ]
+    branches: [ main ]
   pull_request:
-    branches: [ master, main ]
+    branches: [ main ]
 
 jobs:
   build:

README.md

@@ -4,8 +4,8 @@
 A CLI command to invoke the standard help functionality from [oclif/core](https://github.com/oclif/core).
 
 [![Version](https://img.shields.io/npm/v/@oclif/plugin-help.svg)](https://npmjs.org/package/@oclif/plugin-help)
-[![CircleCI](https://circleci.com/gh/oclif/plugin-help/tree/master.svg?style=svg)](https://circleci.com/gh/oclif/plugin-help/tree/master)
-[![Appveyor CI](https://ci.appveyor.com/api/projects/status/github/oclif/plugin-help?branch=master&svg=true)](https://ci.appveyor.com/project/heroku/plugin-help/branch/master)
+[![CircleCI](https://circleci.com/gh/oclif/plugin-help/tree/main.svg?style=svg)](https://circleci.com/gh/oclif/plugin-help/tree/main)
+[![Appveyor CI](https://ci.appveyor.com/api/projects/status/github/oclif/plugin-help?branch=main&svg=true)](https://ci.appveyor.com/project/heroku/plugin-help/branch/main)
 [![Known Vulnerabilities](https://snyk.io/test/npm/@oclif/plugin-help/badge.svg)](https://snyk.io/test/npm/@oclif/plugin-help)
 [![Downloads/week](https://img.shields.io/npm/dw/@oclif/plugin-help.svg)](https://npmjs.org/package/@oclif/plugin-help)
-[![License](https://img.shields.io/npm/l/@oclif/plugin-help.svg)](https://github.com/oclif/plugin-help/blob/master/package.json)
+[![License](https://img.shields.io/npm/l/@oclif/plugin-help.svg)](https://github.com/oclif/plugin-help/blob/main/package.json)