Add GitHub Actions

Author: vearutop

.github/workflows/lint.yml

@@ -0,0 +1,37 @@
+name: lint
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+jobs:
+  run:
+    runs-on: ${{ matrix.operating-system }}
+    strategy:
+      matrix:
+        operating-system: [ 'ubuntu-latest' ]
+        php-versions: [ '7.4' ]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Cache vendor
+        uses: actions/cache@v2
+        with:
+          path: |
+            vendor
+          key: vendor-${{ hashFiles('composer.lock') }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-versions }}
+          ini-values: post_max_size=256M, max_execution_time=180
+          tools: composer
+
+      - name: Populate vendor
+        run: '[ -e vendor ] || composer install'
+
+      - name: Lint
+        run: make lint