chore: update README badges

README.md

@@ -1,12 +1,18 @@
 # env-var
 
+<div align="center">
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 [![Travis CI](https://travis-ci.org/evanshortiss/env-var.svg?branch=master)](https://travis-ci.org/evanshortiss/env-var)
 [![Coverage Status](https://coveralls.io/repos/github/evanshortiss/env-var/badge.svg?branch=master)](https://coveralls.io/github/evanshortiss/env-var?branch=master)
-[![npm version](https://badge.fury.io/js/env-var.svg)](https://www.npmjs.com/package/env-var)
+[![NPM version](https://img.shields.io/npm/v/env-var.svg?style=flat)](https://www.npmjs.com/package/env-var)
 [![TypeScript](https://img.shields.io/badge/%3C%2F%3E-TypeScript-blue.svg)](http://www.typescriptlang.org/)
+
 [![npm downloads](https://img.shields.io/npm/dm/env-var.svg?style=flat)](https://www.npmjs.com/package/env-var)
+[![Known Vulnerabilities](https://snyk.io//test/github/evanshortiss/env-var/badge.svg?targetFile=package.json)](https://snyk.io//test/github/evanshortiss/env-var?targetFile=package.json)
 [![Greenkeeper badge](https://badges.greenkeeper.io/evanshortiss/env-var.svg)](https://greenkeeper.io/)
 
+</div>
+
 Verification, sanatization, and type coercion for environment variables in
 Node.js. Particularly useful in TypeScript environments.