ci: Include files in hidden directories when testing for code changes

.run_on_code_change rules now includes testing for code changes within hidden directories.

This was missing before and changes under .gitlab/ directory didn't trigger the pipeline.

Tested on !10600 (merged) compare :

• without the patch https://gitlab.kitware.com/vtk/vtk/-/pipelines/370559
• with the patch https://gitlab.kitware.com/vtk/vtk/-/pipelines/370884