Switch to Github Actions (#1)

* use github actions to run the grunt tests
* switch to the github actions build badge

.github/workflows/build.yml

@@ -0,0 +1,29 @@
+name: Build
+
+on:
+  push:
+    branches: ['master', 'main']
+  pull_request:
+    branches: ['master', 'main']
+
+jobs:
+  build:
+
+    runs-on: ubuntu-20.04
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - uses: actions/setup-node@v1
+      with:
+        node-version: 14
+
+    - run: npm install -g grunt-cli
+    - run: npm install
+    - run: grunt
+    - run: cp ./coverage/*/lcov.info ./coverage/
+
+    - name: Coveralls
+      uses: coverallsapp/github-action@master
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}

README.md

@@ -2,7 +2,7 @@
 
 <span class="badge-npmversion"><a href="https://npmjs.org/package/@iamcal/ease.js" title="View this project on NPM"><img src="https://img.shields.io/npm/v/@iamcal/ease.js.svg" alt="NPM version" /></a></span>
 <span class="badge-npmdownloads"><a href="https://npmjs.org/package/@iamcal/ease.js" title="View this project on NPM"><img src="https://img.shields.io/npm/dm/@iamcal/ease.js.svg" alt="NPM downloads" /></a></span>
-[![Build Status](https://travis-ci.org/iamcal/ease.js.svg)](https://travis-ci.org/iamcal/ease.js)
+[![Build Status](https://github.com/iamcal/ease.js/actions/workflows/build.yml/badge.svg)](https://github.com/iamcal/ease.js/actions)
 [![Coverage Status](https://coveralls.io/repos/iamcal/ease.js/badge.svg)](https://coveralls.io/r/iamcal/ease.js)
 
 When an object changes position in real life, it rarely moves linearly.