Use GitHub Actions CI (#154)

Travis is taking over an hour to run for some reason.

This PR changes this repo to use GitHub Actions CI instead of Travis CI.

Author: styfle

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [6.x, 14.x]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm install
+    - run: npm test

.travis.yml

@@ -1,6 +1,6 @@
 # ms
 
-[![Build Status](https://travis-ci.org/vercel/ms.svg?branch=master)](https://travis-ci.org/vercel/ms)
+![CI](https://github.com/vercel/ms/workflows/CI/badge.svg)
 
 Use this package to easily convert various time formats to milliseconds.