fix: update file name checker to account for space issue

[LangLangBart]

Description

• Update to fix: avoid common illegal filename characters #110
• the jitterbit/get-changed-files repo is a bit outdated
  • the github workflow throws some warnings to consider changes on the runner
• Update to tj-actions/changed-files
  • Fix bug when filenames contain spaces [BUG] Spaces in file names are not handled correctly tj-actions/changed-files#216

[andy5995]

@LangLangBart You now have admin privileges. I'll step aside and you can consider yourself the primary admin if you like.

[LangLangBart]

• is the bullseye something you have to provide? the workflow runs slow.
  • I would just use the checkout method from checkrefs.yml: (fix) check for non-empty file #108 instead.

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• Commit access makes it easier to fix trivial problems

[andy5995]

• is the bullseye something you have to provide? the workflow runs slow.

  * I would just use the checkout method from [checkrefs.yml: (fix) check for non-empty file #108](https://github.com/0ad-matters/community-maps-2/pull/108) instead.
  

  • Commit access makes it easier to fix trivial problems

bullseye is a self-hosted runner I run on my computer in a docker container (which means workflows won't run when my computer is off), but at this point, I'm sure you'll agree it would make more sense to switch back to a standard GitHub runner.