Replaced Travis CI with GHA.

Author: dblock

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: [dblock]

.github/workflows/rubocop.yml

@@ -0,0 +1,13 @@
+name: Rubocop
+on: [push, pull_request]
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.7
+          bundler-cache: true
+      - run: bundle exec rubocop

.github/workflows/test.yml

@@ -0,0 +1,22 @@
+name: Tests
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.6.5
+          bundler-cache: true
+      - uses: browser-actions/setup-geckodriver@latest
+        with:
+          geckodriver-version: 0.18.0
+      - uses: browser-actions/setup-firefox@latest
+        with:
+          firefox-version: '54.0'
+      - uses: GabrielBB/xvfb-action@v1
+        with:
+          run: |
+            bundle exec rake spec

.travis.yml

@@ -1,7 +1,7 @@
 Grape API on Rack
 =================
 
-[![Build Status](https://travis-ci.org/ruby-grape/grape-on-rack.svg?branch=master)](https://travis-ci.org/ruby-grape/grape-on-rack)
+[![Test](https://github.com/grape/grape-on-rack/actions/workflows/test.yml/badge.svg?branch=master)](https://github.com/grape/grape-on-rack/actions/workflows/test.yml)
 [![Code Climate](https://codeclimate.com/github/ruby-grape/grape-on-rack.svg)](https://codeclimate.com/github/ruby-grape/grape-on-rack)
 
 A [Grape](http://github.com/ruby-grape/grape) API mounted on Rack.