Add baseline.php to list of files which triggers the workflow

Co-authored-by: Copilot <[email protected]>

Author: westonruter

.github/workflows/php-static-analysis.yml

@@ -21,6 +21,7 @@ on:
       # These files configure PHPStan. Changes could affect the outcome.
       - 'phpstan.neon.dist'
       - 'tests/phpstan/base.neon'
+      - 'tests/phpstan/baseline.php'
       # Confirm any changes to relevant workflow files.
       - '.github/workflows/php-static-analysis.yml'
       - '.github/workflows/reusable-php-static-analysis.yml'