switch to github actions

.github/workflows/prs.yml

@@ -0,0 +1,28 @@
+name: CI PR Builds
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+concurrency:
+  group: ${{ github.head_ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ['2.5', '2.6', '2.7', '3.0']
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+      - name: Run tests
+        run: bundle exec rake ci

Rakefile

@@ -5,4 +5,4 @@ RSpec::Core::RakeTask.new(:spec)
 
 require 'coveralls/rake/task'
 Coveralls::RakeTask.new
-task :travis => [:spec, 'coveralls:push']
+task :ci => [:spec, 'coveralls:push']