feat: update README.md and add node 12 to CI

Author: devshawn

.travis.yml

@@ -6,6 +6,7 @@ node_js:
   - '6'
   - '8'
   - '10'
+  - '12'
 install:
   - npm install -g codecov
   - npm install

README.md

@@ -2,7 +2,7 @@
 
 React component for the [dayjs][dayjs] date library.
 
-[![Build Status](https://img.shields.io/travis/devshawn/react-dayjs/master.svg?style=flat-square)](https://travis-ci.org/devshawn/react-dayjs) [![codecov](https://img.shields.io/codecov/c/github/devshawn/react-dayjs/master.svg?style=flat-square)](https://codecov.io/gh/devshawn/react-dayjs)  [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)](https://github.com/devshawn/react-dayjs/blob/master/LICENSE.md)
+[![Build Status](https://img.shields.io/travis/devshawn/react-dayjs/master.svg?style=flat-square)](https://travis-ci.org/devshawn/react-dayjs) [![codecov](https://img.shields.io/codecov/c/github/devshawn/react-dayjs/master.svg?style=flat-square)](https://codecov.io/gh/devshawn/react-dayjs) ![Snyk Vulnerabilities for npm package](https://img.shields.io/snyk/vulnerabilities/npm/react-dayjs.svg?style=flat-square) ![npm](https://img.shields.io/npm/v/react-dayjs.svg?color=blue&style=flat-square) [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)](https://github.com/devshawn/react-dayjs/blob/master/LICENSE.md)
 
 * [Installing](#installing)
 * [Quick Start](#quick-start)