Switch to GitHub actions + prepare release workflow

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: CI
+
+on: [push]
+
+jobs:
+  build:
+    timeout-minutes: 20
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Repo
+        uses: actions/checkout@master
+
+      - name: Setup Node.js 12.x
+        uses: actions/setup-node@master
+        with:
+          node-version: 12.x
+
+      - name: Install dependencies
+        run: yarn
+
+      - name: Test
+        run: yarn test

.github/workflows/release.yml

@@ -0,0 +1,35 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Repo
+        uses: actions/checkout@master
+        with:
+          # This makes Actions fetch all Git history so that Changesets can generate changelogs with the correct commits
+          fetch-depth: 0
+
+      - name: Setup Node.js 12.x
+        uses: actions/setup-node@master
+        with:
+          node-version: 12.x
+
+      - name: Install Dependencies
+        run: yarn
+
+      - name: Create Release Pull Request or Publish to npm
+        id: changesets
+        uses: changesets/action@master
+        with:
+          # This expects you to have a script called release which does a build for your packages and calls changeset publish
+          publish: yarn release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          NPM_TOKEN: ${{ secrets.NPM_TOKEN }}

.gitignore

@@ -4,5 +4,4 @@ example/bundle.js
 example/.nojekyll
 dist
 node_modules
-yarn.lock
 .cache