ci: run cs-fix on the minimum supported PHP

spiral/gh-actions#14 defaults the reusable cs-fix workflow to PHP 8.2 and stops ignoring the PHP platform requirement, so each caller passes its own minimum PHP.

Assisted-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: roxblnfk

.github/workflows/cs-fix.yml

@@ -12,5 +12,7 @@ jobs:
     permissions:
       contents: write
     uses: spiral/gh-actions/.github/workflows/cs-fix.yml@master
+    with:
+      php: '["8.1"]'
 
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