Enable GitHub actions (#159)

Remove travis
diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
new file mode 100644
index 0000000..e93c0ad
--- /dev/null
+++ b/.github/workflows/test-package.yml
@@ -0,0 +1,61 @@
+name: 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 and stable.
+  analyze:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # TODO: enable stable once 2.12 ships!
+        sdk: [dev]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dart-lang/setup-dart@v0.1
+        with:
+          channel: ${{ 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
+        if: always() && steps.install.outcome == 'success'
+
+  test:
+    needs: analyze
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest]
+        # TODO: enable stable once 2.12 ships!
+        sdk: [dev]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dart-lang/setup-dart@v0.1
+        with:
+          channel: ${{ 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'
+      - name: Run Chrome tests
+        run: dart test --platform chrome
+        if: always() && steps.install.outcome == 'success'
diff --git a/.test_config b/.test_config
deleted file mode 100644
index 412fc5c..0000000
--- a/.test_config
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "test_package": true
-}
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index d1307eb..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,22 +0,0 @@
-language: dart
-
-dart:
-  - dev
-
-dart_task:
-  - test: --platform vm,firefox
-  - dartanalyzer: --fatal-infos .
-
-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 4b2afd6..de1d757 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,6 @@
 ## Web Server Middleware for Dart
 
-[![Build Status](https://travis-ci.org/dart-lang/shelf.svg?branch=master)](https://travis-ci.org/dart-lang/shelf)
-[![Coverage Status](https://coveralls.io/repos/dart-lang/shelf/badge.svg?branch=master)](https://coveralls.io/r/dart-lang/shelf)
+[![CI](https://github.com/dart-lang/shelf/workflows/CI/badge.svg?branch=master)](https://github.com/dart-lang/shelf/actions?query=workflow%3ACI+branch%3Amaster)
 
 ## Introduction