feat: Typescript definitions (#25)

BREAKING CHANGE: Before

```js
const graphql = require('@octokit/graphql')
```

Now

```js
const { graphql } = require('@octokit/graphql')
// or: import { graphql } from '@octokit/graphql'
```

.gitignore

@@ -1,4 +1,4 @@
 .nyc_output
 coverage
-dist/
 node_modules/
+pkg/

.travis.yml

@@ -15,39 +15,17 @@ stages:
 
 jobs:
   include:
-    - stage: test
-      node_js: 12
-      script: npm run test
     - node_js: 8
       script: npm run test
     - node_js: 10
-      env: Node 10, coverage upload
-      script:
-        - npm run test
-        - npm run coverage:upload
-    - node_js: lts/*
-      addons:
-        apt:
-          packages:
-            # Ubuntu 16+ does not install this dependency by default, so we need to install it ourselves
-            - libgconf-2-4
-      env: browser tests
-      script:
-        - npm run test:browser
-    - node_js: lts/*
-      sudo: required
-      addons:
-        chrome: stable
-      env: bundle size
-      script:
-        - npm run build
-        - npx bundlesize
+      script: npm run test
+    - node_js: 12
+      script: npm run test
 
     # release stage: run semantic release & update the docs
     - stage: release
       node_js: lts/*
       env: semantic-release
       script:
         - npm run build
-        - npm run bundle-report
-        - npx semantic-release
+        - cd pkg && ../node_modules/.bin/semantic-release