Previously, we'd cache the last successfully downloaded version of a path config. This causes an issue when a user updates versions (e.g. path-config-v6.json to path-config-v7.json). Instead of saving the last successfully downloaded version, we now use the path's last component (i.e. the filename) for cache purposes.
Turbo iOS PR: https://github.com/hotwired/turbo-ios/pull/215