Create code-style.yml

Same CS test that was done in travis.

.github/workflows/code-style.yml

@@ -0,0 +1,25 @@
+name: code-style
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  php-cs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        name: Checkout repository
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.2'
+
+      - uses: ramsey/composer-install@v2
+        with:
+          dependency-versions: 'highest'
+
+      - name: Check Code Style
+        run: ./bin/phpcs -p --extensions=php --standard=PSR2 --error-severity=1 --warning-severity=0 ./src ./tests;