Add travis and codecov

Author: weirdpattern

.travis.yml

@@ -1,16 +1,13 @@
 language: node_js
 node_js:
-  - "4"
-  - "5"
-  - "6"
-  - "7"
   - "8"
   - "9"
   - "10"
-  - "11"
-  - "latest"
+install:
+  - npm install -g codecov
 script:
-  - yarn run test:verbose
+  - yarn run test:coverage
+  - codecov
 git:
   depth: 3
 cache:

README.md

@@ -2,6 +2,7 @@
 
 [![NPM badge](https://img.shields.io/npm/v/gatsby-remark-embed-gist.svg?style=flat-square)](https://www.npmjs.com/package/gatsby-remark-embed-gist)
 [![Travis badge](https://img.shields.io/travis/weirdpattern/gatsby-remark-embed-gist.svg?branch=master&style=flat-square)](https://travis-ci.org/weirdpattern/gatsby-remark-embed-gist)
+[![codecov](https://codecov.io/gh/weirdpattern/gatsby-remark-embed-gist/branch/master/graph/badge.svg)](https://codecov.io/gh/weirdpattern/gatsby-remark-embed-gist)
 
 This plugin allows content authors to embed [Gist](https://gist.github.com/) 
 snippets.

package.json

@@ -170,7 +170,6 @@
     "verbose": false,
     "resetMocks": true,
     "resetModules": true,
-    "collectCoverage": false,
     "collectCoverageFrom": [
       "src/*.{j,t}s{,x}",
       "!**/*.min.js",