Add workflow ci (#30)

* Add workflow ci
* Delete travis yml

Co-authored-by: Sara Gfrörer <[email protected]>

Author: srmnq

.github/workflows/ci.yml

@@ -0,0 +1,41 @@
+name: CI Tests
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Validate composer.json and composer.lock
+        run: composer validate
+
+      - name: Get Composer Cache Directory
+        id: composer-cache
+        run: |
+          echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress
+
+      - name: Run test suite
+        run: composer test
+
+      - name: Run phpstan
+        run: composer analyze
+
+      - name: Run codestyle checker
+        run: composer cs-check
+
+      - uses: actions/cache@v1
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-composer-