Do not override existing index pages

[paulbrimicombe]

🧐 What?

• Don't generate an index file for a directory if one has already been provided in the source repository

🛠 How

• Test whether an index.html file already exists in a folder before generating one

🐞 Related issue

#90

📓 Notes

• I've upgraded jest because the existing version wouldn't run on the latest version of Node JS 18 — see this build
• I also ran npm audit fix to fix the security vulnerabilities

[stephegn]

Thanks for adding the note to the README. When the tests pass (and after lunch 😅) I'll get this merged and tagged.
I'll probably wait for your other PR before getting this pushed out to our internal system.