😒 chore(README): Link to main branch.

README.md

@@ -1,7 +1,7 @@
 :christmas_tree: [@aureooms/js-red-black-tree](https://aureooms.github.io/js-red-black-tree)
 ==
 
-<img src="https://cdn.rawgit.com/aureooms/js-red-black-tree/master/media/sketch.svg" width="864">
+<img src="https://cdn.rawgit.com/aureooms/js-red-black-tree/main/media/sketch.svg" width="864">
 
 ```js
 let tree = RedBlackTree.from( increasing , range( 100000 ) ) ;
@@ -11,17 +11,17 @@ Red-black tree library for JavaScript.
 See [documentation](https://aureooms.github.io/js-red-black-tree/index.html).
 Parent is [@aureooms/js-bst](https://github.com/aureooms/js-bst).
 
-[![License](https://img.shields.io/github/license/aureooms/js-red-black-tree.svg)](https://raw.githubusercontent.com/aureooms/js-red-black-tree/master/LICENSE)
+[![License](https://img.shields.io/github/license/aureooms/js-red-black-tree.svg)](https://raw.githubusercontent.com/aureooms/js-red-black-tree/main/LICENSE)
 [![Version](https://img.shields.io/npm/v/@aureooms/js-red-black-tree.svg)](https://www.npmjs.org/package/@aureooms/js-red-black-tree)
-[![Build](https://img.shields.io/travis/aureooms/js-red-black-tree/master.svg)](https://travis-ci.org/aureooms/js-red-black-tree/branches)
+[![Build](https://img.shields.io/travis/aureooms/js-red-black-tree/main.svg)](https://travis-ci.org/aureooms/js-red-black-tree/branches)
 [![Dependencies](https://img.shields.io/david/aureooms/js-red-black-tree.svg)](https://david-dm.org/aureooms/js-red-black-tree)
 [![Dev dependencies](https://img.shields.io/david/dev/aureooms/js-red-black-tree.svg)](https://david-dm.org/aureooms/js-red-black-tree?type=dev)
 [![GitHub issues](https://img.shields.io/github/issues/aureooms/js-red-black-tree.svg)](https://github.com/aureooms/js-red-black-tree/issues)
 [![Downloads](https://img.shields.io/npm/dm/@aureooms/js-red-black-tree.svg)](https://www.npmjs.org/package/@aureooms/js-red-black-tree)
 
 [![Code issues](https://img.shields.io/codeclimate/issues/aureooms/js-red-black-tree.svg)](https://codeclimate.com/github/aureooms/js-red-black-tree/issues)
 [![Code maintainability](https://img.shields.io/codeclimate/maintainability/aureooms/js-red-black-tree.svg)](https://codeclimate.com/github/aureooms/js-red-black-tree/trends/churn)
-[![Code coverage (cov)](https://img.shields.io/codecov/c/gh/aureooms/js-red-black-tree/master.svg)](https://codecov.io/gh/aureooms/js-red-black-tree)
+[![Code coverage (cov)](https://img.shields.io/codecov/c/gh/aureooms/js-red-black-tree/main.svg)](https://codecov.io/gh/aureooms/js-red-black-tree)
 [![Code technical debt](https://img.shields.io/codeclimate/tech-debt/aureooms/js-red-black-tree.svg)](https://codeclimate.com/github/aureooms/js-red-black-tree/trends/technical_debt)
 [![Documentation](https://aureooms.github.io/js-red-black-tree/badge.svg)](https://aureooms.github.io/js-red-black-tree/source.html)
 [![Package size](https://img.shields.io/bundlephobia/minzip/@aureooms/js-red-black-tree)](https://bundlephobia.com/result?p=@aureooms/js-red-black-tree)