use github-ci instead of travis-ci

Author: dbu

.github/workflows/ci.yml

@@ -0,0 +1,41 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - 'master'
+    tags:
+      - '[0-9].[0-9]+'
+  pull_request:
+
+jobs:
+  test:
+    name: "PHPUnit"
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-version: ['7.2', '7.3', '7.4', '8.0']
+        include:
+          - php-version: '7.2'
+            composer-flags: '--prefer-stable --prefer-lowest'
+    steps:
+      - name: Check out code into the workspace
+        uses: actions/checkout@v2
+      - name: Setup PHP ${{ matrix.php-version }}
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+      - name: Validate composer.json
+        run: composer validate --strict --no-check-lock
+      - name: Composer cache
+        uses: actions/cache@v2
+        with:
+          path: ${{ env.HOME }}/.composer/cache
+          key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}
+      - name: Install dependencies
+        run: composer update ${{ matrix.composer-flags }} --prefer-dist --no-interaction
+      - name: PHPStan
+        if: ${{ matrix.php-version == '8.0' }}
+        run: composer phpstan-all
+      - name: Run tests
+        run: composer phpunit