Add github actions, remove travis. Closes #52 (#53)

* add github actions, remove travis

* test on ppc64le

* Revert "test on ppc64le"

This reverts commit 28d6b4e.

.github/workflows/ci.yml

@@ -0,0 +1,15 @@
+name: CI
+on: [push]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: ['10', '12', '14', '16']
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node }}
+      - run: npm ci
+      - run: npm test

README.md

@@ -3,11 +3,7 @@
 [Brace expansion](https://www.gnu.org/software/bash/manual/html_node/Brace-Expansion.html), 
 as known from sh/bash, in JavaScript.
 
-[![build status](https://secure.travis-ci.org/juliangruber/brace-expansion.svg)](http://travis-ci.org/juliangruber/brace-expansion)
 [![downloads](https://img.shields.io/npm/dm/brace-expansion.svg)](https://www.npmjs.org/package/brace-expansion)
-[![Greenkeeper badge](https://badges.greenkeeper.io/juliangruber/brace-expansion.svg)](https://greenkeeper.io/)
-
-[![testling badge](https://ci.testling.com/juliangruber/brace-expansion.png)](https://ci.testling.com/juliangruber/brace-expansion)
 
 ## Example