Revert "Make URLs case sensitive"
This actually doesn't help for two reasons:
- the Rake task is broken, as both filenames are the same
- Netlify doesn't like mixed-case names https://www.jvt.me/posts/2019/11/11/gotcha-netlify-lowercase/
This should've been done at the time of www-api!31 (merged), but wasn't.
This reverts commit b82db8dc.