ci: add GitHub workflows to validate PRs and pushes to main

.github/workflows/ci.lint.yml

@@ -0,0 +1,25 @@
+name: Lint
+
+on:
+  push:
+    branches: [ 'main' ]
+  pull_request:
+    branches: [ 'main' ]
+
+permissions:
+  contents: read
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.0'
+          bundler-cache: true
+
+      - name: Run RuboCop
+        run: bundle exec rubocop

.github/workflows/ci.test.yml

@@ -0,0 +1,39 @@
+name: Test
+
+on:
+  push:
+    branches: [ 'main' ]
+  pull_request:
+    branches: [ 'main' ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ['2.6', '2.7', '3.0']
+        ffmpeg-version: ['6.0.1', '5.1.1', '4.4.1', '3.4.2']
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+
+      - name: Install FFMPEG
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y wget
+          wget https://johnvansickle.com/ffmpeg/releases/ffmpeg-${{ matrix.ffmpeg-version }}-amd64-static.tar.xz
+          tar -xf ffmpeg-${{ matrix.ffmpeg-version }}-amd64-static.tar.xz
+          sudo mv ffmpeg-${{ matrix.ffmpeg-version }}-amd64-static/ffmpeg /usr/local/bin/ffmpeg
+          sudo mv ffmpeg-${{ matrix.ffmpeg-version }}-amd64-static/ffprobe /usr/local/bin/ffprobe
+          rm -rf ffmpeg-${{ matrix.ffmpeg-version }}-amd64-static.tar.xz ffmpeg-${{ matrix.ffmpeg-version }}-amd64-static
+
+      - name: Run RSpec
+        run: bundle exec rspec