Adjust php matrix of coding-standards workflow

Author: paulbalandan

.github/workflows/test-coding-standards.yml

@@ -28,8 +28,8 @@ jobs:
       fail-fast: false
       matrix:
         php-version:
-          - '7.4'
           - '8.0'
+          - '8.1'
 
     steps:
       - name: Checkout