Correctly define github action

Author: jswift

.github/workflows/php.yml

@@ -1,12 +1,17 @@
-code-standards:
-  runs-on: ubuntu-latest
-  steps:
-    - name: Checkout code
-      uses: actions/checkout@v2
-      with:
-        fetch-depth: 0
-    - name: Code Standards Test
-      uses: docker://aligent/code-standards-pipe-php:7.4
-      env:
-        STANDARDS: "Magento2"
-        SKIP_DEPENDENCIES: "true"
+name: Run PHP Static Analysis
+
+on: pull_request
+  
+jobs:
+  code-standards:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Code Standards Test
+        uses: docker://aligent/code-standards-pipe-php:7.4
+        env:
+          STANDARDS: "Magento2"
+          SKIP_DEPENDENCIES: "true"