fix: try only to PR files with NODE_VERSION change

[nschonni]

Don't think this actually will resolve it, but this diff command will limit it to only the files that have changed versions. Proper solution probably needs some re-work that would require the migration from SH to JS for update.sh

[SimenB]

Proper solution probably needs some re-work that would require the migration from SH to JS for update.sh

To the surprise of no one, this is my preferred solution 😃

Or, I'd prefer TS and ts-node or something. But migration to JS would be a great improvement to maintainability (we could do inline jsdoc which helps IDE integration without needing an installation and verification step)