Build/Test Tools: Use the new concurrency setting for GitHub Actions.

The new `concurrency` setting can be used to ensure only a single workflow run or job is in progress. When used in combination with the `cancel-in-progress` setting, incomplete workflow runs can be cancelled automatically to prevent running workflows unnecessarily.

The workflows that take longer to run previously had this built into a step and utilized a 3rd-party action. Now that this is natively supported by GitHub Actions, using that is preferred.

This option is currently in beta, but is stable enough to use in our workflows for the time being.

Props ocean90.
Fixes #53080.

git-svn-id: https://develop.svn.wordpress.org/trunk@50930 602fd350-edb4-49c9-b593-d223f7449a82

.github/workflows/coding-standards.yml

@@ -34,6 +34,13 @@ on:
       - '.github/workflows/*.yml'
   workflow_dispatch:
 
+# Cancels all previous workflow runs for pull requests that have not completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name for pull requests
+  # or the commit hash for any other events.
+  group: ${{ github.workflow }}-${{ github.event_name == 'pull_request' && github.head_ref || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   # Runs PHP coding standards checks.
   #