allow manual trigger, cancel on multiple pushes

Author: ylebre

.github/workflows/linting-php.yml

@@ -4,7 +4,15 @@ name: Linting PHP
 on:
   - push
   - pull_request
+  # Allow manually triggering the workflow.
+  - workflow_dispatch
 
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+  
 jobs:
   lint-php:
     runs-on: ubuntu-20.04