Checklist

• I have ensured my pull request is not behind the main or master branch of the original repository.
• I have rebased all commits where necessary so that reviewing this pull request can be done without having to merge it first.
• I have written a commit message that passes commitlint linting.
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In response to #186, this attempts to update path-to-regexp from version 6 to version 8. This PR is incomplete (a few difficulties were encountered) and the original issue seems to have been resolved.

Submitting this PR just in case it may happen to be useful to anyone for any reason at all.

I don't know how to describe optional end-slash in paths used with path-to-regexp@8.1.0 and would request advice there if trying to complete this PR. Numerous experiments failed.

Thank you! :) Feel free to close or ignore this