Add GitHub Actions CI workflow

Author: epologee

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  rubocop:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '.ruby-version'
+          bundler-cache: true
+      - run: bundle exec rubocop --parallel
+
+  rspec:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '.ruby-version'
+          bundler-cache: true
+      - run: bundle exec rspec

README.md

@@ -1,5 +1,6 @@
 # S2 Ruby
 
+[![Tests](https://github.com/stekker/s2-ruby/actions/workflows/ci.yml/badge.svg)](https://github.com/stekker/s2-ruby/actions/workflows/ci.yml)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](LICENSE.txt)
 [![Ruby](https://img.shields.io/badge/Ruby-3.3+-red.svg)](s2-ruby.gemspec)