Add PHP 8 testcase and migrate to github actions (#193)

* Add PHP 8 testcase and migrate to github actions

Author: alexander-schranz

.github/workflows/test-application.yaml

@@ -0,0 +1,43 @@
+name: Test application
+
+on:
+    pull_request:
+    push:
+        branches:
+            - 'master'
+            - '[0-9]+.x'
+            - '[0-9]+.[0-9]+'
+            - '[0-9]+.[0-9]+.x'
+
+jobs:
+    test:
+        name: 'PHP ${{ matrix.php-version }} ${{ matrix.dependencies}}'
+        runs-on: ubuntu-20.04
+
+        strategy:
+            fail-fast: false
+            matrix:
+                include:
+                    - php-version: '7.1'
+                      dependencies: 'lowest'
+                    - php-version: '7.4'
+                    - php-version: '8.0'
+
+        steps:
+            - name: Checkout project
+              uses: actions/checkout@v2
+
+            - name: Install and configure PHP
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: ${{ matrix.php-version }}
+                  tools: 'composer:v2'
+
+            - name: Install dependencies with Composer
+              uses: ramsey/composer-install@v1
+              with:
+                  dependency-versions: ${{ matrix.dependencies }}
+                  composer-options: --prefer-dist
+
+            - name: Execute test cases
+              run: vendor/bin/phpunit