Uploading custom feed icons fails silently

Uploading custom feed icons fails silently on both my docker install (v22.12-8ea537123) and the demo setup.

video: ScreenCapture 19 12 2022 16 03 39 - YouTube

the icon uploads just fine, the problem is browser cache-related. i.e. the cache is not invalidated properly.

fix with some cache-related improvements: * bring back cache-busting for feed icons based on timestamp ยท d373b7b452 - tt-rss - Tiny Tiny RSS