Migrate to GitHub Actions (#21)

* Migrate to GitHub Actions

* Delete .travis.yml

* Replace Travis badge
diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
new file mode 100644
index 0000000..c3808a4
--- /dev/null
+++ b/.github/workflows/test-package.yml
@@ -0,0 +1,85 @@
+name: Dart CI
+
+on:
+  # Run on PRs and pushes to the default branch.
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+  schedule:
+    - cron: "0 0 * * 0"
+
+env:
+  PUB_ENVIRONMENT: bot.github
+
+jobs:
+  # Check code formatting and static analysis on a single OS (linux)
+  # against Dart dev.
+  analyze:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        sdk: [dev]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dart-lang/setup-dart@v0.3
+        with:
+          sdk: ${{ matrix.sdk }}
+      - id: install
+        name: Install dependencies
+        run: dart pub get
+      - name: Check formatting
+        run: dart format --output=none --set-exit-if-changed .
+        if: always() && steps.install.outcome == 'success'
+      - name: Analyze code
+        run: dart analyze --fatal-infos
+        if: always() && steps.install.outcome == 'success'
+
+  # Run tests on a matrix consisting of two dimensions:
+  # 1. OS: ubuntu-latest, (macos-latest, windows-latest)
+  # 2. release channel: dev
+  test:
+    needs: analyze
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        # Add macos-latest and/or windows-latest if relevant for this package.
+        os: [ubuntu-latest]
+        sdk: [dev]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dart-lang/setup-dart@v0.3
+        with:
+          sdk: ${{ matrix.sdk }}
+      - id: install
+        name: Install dependencies
+        run: dart pub get
+      - name: Run VM tests
+        run: dart test --platform vm
+        if: always() && steps.install.outcome == 'success'
+
+  # Run tests on a matrix consisting of two dimensions:
+  # 1. OS: ubuntu-latest, (macos-latest, windows-latest)
+  # 2. release channel: 2.0.0
+  test-legacy-sdk:
+    needs: analyze
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        # Add macos-latest and/or windows-latest if relevant for this package.
+        os: [ubuntu-latest]
+        sdk: [2.0.0]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dart-lang/setup-dart@v0.3
+        with:
+          sdk: ${{ matrix.sdk }}
+      - id: install
+        name: Install dependencies
+        run: pub get
+      - name: Run VM tests
+        run: pub run test --platform vm
+        if: always() && steps.install.outcome == 'success'
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 81986a0..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,23 +0,0 @@
-language: dart
-
-dart:
-  - dev
-  - 2.0.0
-
-dart_task:
-  - test
-  - dartanalyzer: --fatal-infos --fatal-warnings .
-
-matrix:
-  include:
-  # Only validate formatting using the dev release
-  - dart: dev
-    dart_task: dartfmt
-
-# Only building master means that we don't run two builds for each pull request.
-branches:
-  only: [master]
-
-cache:
- directories:
-   - $HOME/.pub-cache
diff --git a/README.md b/README.md
index 9417820..03c337f 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 ## Proxy for Shelf
 
-[![Build Status](https://travis-ci.org/dart-lang/shelf_proxy.svg?branch=master)](https://travis-ci.org/dart-lang/shelf_proxy)
+[![Build Status](https://github.com/dart-lang/shelf_proxy/workflows/Dart%20CI/badge.svg)](https://github.com/dart-lang/shelf_proxy/actions?query=workflow%3A"Dart+CI"+branch%3Amaster)
 
 `shelf_proxy` is a [Shelf][] handler that proxies requests to an external
 server. It can be served directly and used as a proxy server, or it can be