feat: php linter on pull requests

.github/workflows/phplint.yml

@@ -0,0 +1,13 @@
+name: PHP Linting
+on:
+  pull_request:
+    branches: [master, develop]
+  push:
+    branches: [master]
+
+jobs:
+  phplint:
+    runs-on: ubuntu-latest
+    steps:
+        - uses: actions/checkout@v1
+        - uses: michaelw90/PHP-Lint@master