Add GitHub CI setup (#139)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: CI
+on:
+  - push
+  - pull_request
+jobs:
+  test:
+    name: Node.js ${{ matrix.node-version }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version:
+          - 14
+          - 12
+          - 10
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm install
+      - run: npm test

readme.md

@@ -11,7 +11,7 @@
 <br>
 <br>
 
-[![Build Status](https://travis-ci.com/sindresorhus/type-fest.svg?branch=master)](https://travis-ci.com/sindresorhus/type-fest)
+[![Build Status](https://github.com/sindresorhus/type-fest/workflows/CI/badge.svg?branch=master)](https://github.com/sindresorhus/type-fest/actions?query=branch%3Amaster+workflow%3ACI)
 [![](https://img.shields.io/badge/unicorn-approved-ff69b4.svg)](https://giphy.com/gifs/illustration-rainbow-unicorn-26AHG5KGFxSkUWw1i)
 <!-- Commented out until they actually show anything
 [![npm dependents](https://badgen.net/npm/dependents/type-fest)](https://www.npmjs.com/package/type-fest?activeTab=dependents) [![npm downloads](https://badgen.net/npm/dt/type-fest)](https://www.npmjs.com/package/type-fest)