Migrate CI from CircleCI to Github Actions

.github/actions/composer-install/action.yml

@@ -0,0 +1,20 @@
+name: Install dependencies
+description: Install dependencies with Composer
+runs:
+  using: 'composite'
+  steps:
+    - run: composer validate --strict
+      shell: bash
+
+    - id: composer-cache
+      run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+      shell: bash
+
+    - uses: actions/cache@v2
+      with:
+        path: ${{ steps.composer-cache.outputs.dir }}
+        key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+        restore-keys: ${{ runner.os }}-composer-
+
+    - run: composer install -a -n --no-progress
+      shell: bash

.github/workflows/ci.yml

@@ -0,0 +1,91 @@
+name: Quality checks
+
+on:
+  pull_request:
+
+jobs:
+  test:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+          - "7.4"
+          - "8.0"
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          tools: composer:v2
+
+      - uses: ./.github/actions/composer-install
+
+      - name: Run unit tests
+        run: make test-unit
+
+      - name: Run mutation tests
+        run: make test-mutation
+
+      - name: Run integration tests
+        run: make test-integration
+
+  static-analysis:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 7.4
+          tools: composer:v2
+
+      - uses: ./.github/actions/composer-install
+
+      - name: Run static analysis
+        run: make static-analysis
+
+  style-check:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 7.4
+          tools: composer:v2
+
+      - uses: ./.github/actions/composer-install
+
+      - name: Run style checker
+        run: make cs-check
+
+  composer-require-checker:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 7.4
+          tools: composer:v2
+
+      - uses: ./.github/actions/composer-install
+
+      - name: Run ComposerRequireChecker
+        run: make composer-require-checker
+