Update dependencies to enable Greenkeeper 🌴 (#20)

* chore(package): update dependencies

https://greenkeeper.io/

* chore(travis): whitelist greenkeeper branches 

https://greenkeeper.io/

* docs(readme): add Greenkeeper badge 

https://greenkeeper.io/

* Update yarn.lock, fix badges

.travis.yml

@@ -12,6 +12,7 @@ sudo: false
 branches:
   only:
     - master
+    - /^greenkeeper/.*$/
 
 script:
   - yarn test

README.md

@@ -1,7 +1,8 @@
 # GraphBrainz
 
-[![build status](https://img.shields.io/travis/exogen/graphbrainz.svg)](https://travis-ci.org/exogen/graphbrainz)
+[![build status](https://img.shields.io/travis/exogen/graphbrainz/master.svg)](https://travis-ci.org/exogen/graphbrainz)
 [![coverage](https://img.shields.io/codecov/c/github/exogen/graphbrainz.svg)](https://codecov.io/gh/exogen/graphbrainz)
+[![Greenkeeper badge](https://badges.greenkeeper.io/exogen/graphbrainz.svg)](https://greenkeeper.io/)
 [![npm version](https://img.shields.io/npm/v/graphbrainz.svg)](https://www.npmjs.com/package/graphbrainz)
 [![license](https://img.shields.io/npm/l/graphbrainz.svg)](https://github.com/exogen/graphbrainz/blob/master/LICENSE)
 

package.json

@@ -80,7 +80,7 @@
     "retry": "^0.10.1"
   },
   "devDependencies": {
-    "ava": "^0.18.2",
+    "ava": "^0.19.0",
     "babel-cli": "^6.24.0",
     "babel-eslint": "^7.2.1",
     "babel-plugin-istanbul": "^4.1.1",
@@ -91,14 +91,14 @@
     "coveralls": "^2.13.0",
     "cross-env": "^4.0.0",
     "doctoc": "^1.3.0",
-    "graphql-markdown": "^2.0.0",
+    "graphql-markdown": "^2.0.1",
     "nodemon": "^1.11.0",
     "nyc": "^10.2.0",
     "rimraf": "^2.6.1",
     "sepia": "^2.0.2",
     "sinon": "^2.1.0",
     "snazzy": "^6.0.0",
-    "standard": "^9.0.2"
+    "standard": "^10.0.0"
   },
   "standard": {
     "parser": "babel-eslint"

test/api/musicbrainz.js

@@ -60,7 +60,7 @@ test('shouldRetry() retries only transient local connection issues', t => {
 
 test('rejects non-MusicBrainz errors', t => {
   const client = new MusicBrainz({ baseURL: '$!@#$' })
-  t.throws(client.get('artist/5b11f4ce-a62d-471e-81fc-a69a8278c7da'), Error)
+  return t.throws(client.get('artist/5b11f4ce-a62d-471e-81fc-a69a8278c7da'), Error)
 })
 
 test('uses the default error impementation if there is no JSON error', t => {