Switch to GitHub Actions CI.

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: Build/test
+on:
+  push:
+    branches:
+      - "**"
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: true
+      matrix:
+        os: [macos-latest, ubuntu-latest]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 14
+      - run: npm install
+      - run: npm test
+  test_windows:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 14
+      - run: npm install
+      - run: npm run-script test-windows

README.md

@@ -1,8 +1,7 @@
 tree-sitter-javascript
 ===========================
 
-[![Build Status](https://github.com/tree-sitter/tree-sitter-javascript/workflows/build/badge.svg)](https://github.com/tree-sitter/tree-sitter-javascript/actions?query=workflow%3Abuild)
-[![Build status](https://ci.appveyor.com/api/projects/status/42kwnan77rtf8144/branch/master?svg=true)](https://ci.appveyor.com/project/maxbrunsfeld/tree-sitter-javascript/branch/master)
+[![Build/test](https://github.com/tree-sitter/tree-sitter-javascript/actions/workflows/ci.yml/badge.svg)](https://github.com/tree-sitter/tree-sitter-javascript/actions/workflows/ci.yml)
 
 JavaScript grammar for [tree-sitter][].
 
@@ -11,4 +10,4 @@ JavaScript grammar for [tree-sitter][].
 References
 
 * [The ESTree Spec](https://github.com/estree/estree)
-* [The ECMAScript 2015 Spec](http://www.ecma-international.org/ecma-262/6.0/)
+* [The ECMAScript 2015 Spec](http://www.ecma-international.org/ecma-262/6.0/)