docs: Add code fences (anishkny#46)

* docs(changelog): Add code fences

* docs(README): Point to GitHub Security in badge

Author: anishkny

CHANGELOG.md

@@ -13,18 +13,22 @@ This should simplify usage.
 
 Before:
 
+```
 [
   module.exports.incrementFavoritesCount,
   module.exports.decrementFavoritesCount,
 ] = integrify({
   rule: 'MAINTAIN_COUNT',
   ...
+```
 
 After:
 
+```
 module.exports.maintainFavoritesCount = integrify({
   rule: 'MAINTAIN_COUNT',
   ...
+```
 
 ### Features
 

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://travis-ci.com/anishkny/integrify.svg?branch=master)](https://travis-ci.com/anishkny/integrify)
 [![Coverage Status](https://coveralls.io/repos/github/anishkny/integrify/badge.svg?branch=master)](https://coveralls.io/github/anishkny/integrify?branch=master)
 [![Greenkeeper badge](https://badges.greenkeeper.io/anishkny/integrify.svg)](https://greenkeeper.io/)
-[![Known Vulnerabilities](https://snyk.io/test/github/anishkny/integrify/badge.svg?targetFile=package.json)](https://snyk.io/test/github/anishkny/integrify?targetFile=package.json)
+[![Security](https://img.shields.io/badge/security-GitHub-blue)](https://github.com/anishkny/integrify/network/alerts)
 [![npm package](https://img.shields.io/npm/v/integrify.svg)](https://www.npmjs.com/package/integrify)
 [![Mentioned in Awesome Firebase](https://awesome.re/mentioned-badge.svg)](https://github.com/jthegedus/awesome-firebase)