ci-check script is rather slow

[junedev]

The script ci-check which in turn calls some other scripts runs for every exercise that was changed in a PR. That means e.g. for PRs that include some files being synced for all exercises, the script runs for all exercises. As far as I could see, this consistently takes 10-15min when run as part of the GitHub Actions.

Examples:

• https://github.com/exercism/javascript/runs/4600717991?check_suite_focus=true
• https://github.com/exercism/javascript/runs/4679060545?check_suite_focus=true

This is a bit annoying when a maintainer wants to get something done quickly so maybe someone has an idea what could be done to improve the performance.