Replace travis build with github action

Author: Andreas Frömer

.github/workflows/continuous-integration.yml

@@ -0,0 +1,90 @@
+name: CI Pipeline
+on:
+  push:
+    branches:
+      - "[0-9]+.[0-9]+.x"
+  pull_request:
+
+jobs:
+
+  coding-standard:
+    name: "Coding Standard"
+    runs-on: "${{ matrix.operating-system }}"
+    strategy:
+      fail-fast: true
+      matrix:
+        operating-system: ['ubuntu-latest']
+        php-version: ['7.4']
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          tools: "composer:v2"
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Check codestyle
+        run: vendor/bin/phpcs -s
+
+  static-analysis:
+    name: "Static Analysis"
+    runs-on: "${{ matrix.operating-system }}"
+
+    strategy:
+      fail-fast: true
+      matrix:
+        php-version: ['7.4']
+        operating-system: ['ubuntu-latest']
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          tools: "composer:v2"
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Analyze code with static-analysis
+        run: vendor/bin/phpstan analyse --no-progress
+
+  unit-tests:
+    name: "Unit Tests"
+
+    runs-on: "${{ matrix.operating-system }}"
+    continue-on-error: "${{ matrix.experimental }}"
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version: ["7.2", "7.3", "7.4", "8.0"]
+        operating-system: "ubuntu-latest"
+        experimental: [false]
+        include:
+          - php: "8.0"
+            composer-options: "--ignore-platform-req=php"
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          tools: "composer:v2"
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader ${{ matrix.composer-options }}
+
+      - name: Execute tests
+        run: vendor/bin/phpunit --colors=always --coverage-text