add codecov reporting

Author: Kent C. Dodds

.travis.yml

@@ -11,3 +11,5 @@ notifications:
   email: false
 script:
   - npm run validate
+after_success:
+  - npm run report-coverage

package.json

@@ -11,6 +11,7 @@
     "build:umd.min": "webpack --output-filename index.umd.min.js -p",
     "test": "cross-env NODE_ENV=test nyc mocha",
     "watch:test": "mocha --watch",
+    "report-coverage": "cat ./coverage/lcov.info | codecov",
     "lint": "eslint src",
     "validate": "npm-run-all --parallel test lint build"
   },
@@ -41,6 +42,7 @@
     "babel-preset-es2015": "6.9.0",
     "babel-register": "6.11.6",
     "chai": "3.5.0",
+    "codecov": "1.0.1",
     "cross-env": "2.0.0",
     "eslint": "3.2.0",
     "eslint-config-kentcdodds": "^9.0.0",