MNT Use GitHub Actions CI

.github/workflows/ci.yml

@@ -0,0 +1,19 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+  # Every day at 4:00pm UTC
+  schedule:
+    - cron: '0 16 * * *'
+
+jobs:
+  ci:
+    name: CI
+    # Only run cron on the silverstripe account
+    if: (github.event_name == 'schedule' && startsWith(github.repository, 'silverstripe/')) || (github.event_name != 'schedule')
+    uses: silverstripe/gha-ci/.github/workflows/ci.yml@v1
+    with:
+      # installer contains a sample behat.yml file, though there are no behat tests to run
+      endtoend: false

.github/workflows/keepalive.yml

@@ -0,0 +1,17 @@
+name: Keepalive
+
+on:
+  workflow_dispatch:
+  # The 8th of every month at 4:50pm UTC
+  schedule:
+    - cron: '50 16 8 * *'
+
+jobs:
+  keepalive:
+    name: Keepalive
+    # Only run cron on the silverstripe account
+    if: (github.event_name == 'schedule' && startsWith(github.repository, 'silverstripe/')) || (github.event_name != 'schedule')
+    runs-on: ubuntu-latest
+    steps:
+      - name: Keepalive
+        uses: silverstripe/gha-keepalive@v1

README.md

@@ -1,6 +1,6 @@
 ## Overview
 
-[![Build Status](https://api.travis-ci.com/silverstripe/silverstripe-installer.svg?branch=4)](https://travis-ci.com/silverstripe/silverstripe-installer)
+[![CI](https://github.com/silverstripe/silverstripe-installer/actions/workflows/ci.yml/badge.svg)](https://github.com/silverstripe/silverstripe-installer/actions/workflows/ci.yml)
 
 Base project folder for a SilverStripe ([http://silverstripe.org](http://silverstripe.org)) installation. Required modules are installed via [http://github.com/silverstripe/recipe-cms](http://github.com/silverstripe/recipe-cms). For information on how to change the dependencies in a recipe, please have a look at [https://github.com/silverstripe/recipe-plugin](https://github.com/silverstripe/recipe-plugin). In addition, installer includes [theme/simple](https://github.com/silverstripe-themes/silverstripe-simple) as a default theme.