Features:
* Support for thematic/adaptive icons for launcher (#513, thanks to @daedric7 for reporting)
* Custom per-subscription notification settings incl. sounds, DND, etc. (#6, thanks to @doits)
* Insistent notifications that ring until dismissed (#417, thanks to @danmed for reporting)

Bug fixes + maintenance:
* Upgrade Android dependencies and build toolchain to SDK 33 (no ticket)
* Simplify F-Droid build: Disable tasks for Google Services (#516, thanks to @markosopcic)
* Android 13: Ask for permission to post notifications (#508)
* Android 13: Do not allow swiping away the foreground notification (#521, thanks to @alexhorner for reporting)
* Android 5 (SDK 21): Fix crash on unsubscribing (#528, thanks to Roger M. for reporting)
* Remove timestamp when copying message text (#471, thanks to @wunter8)
* Fix auto-delete if some icons do not exist anymore (#506)
* Fix notification icon color (#480, thanks to @s-h-a-r-d for reporting)
* Fix topics do not re-subscribe to Firebase after restoring from backup (#511)
* Fix crashes from large images (#474, thanks to @daedric7 for reporting)
* Fix notification click opens wrong subscription (#261, thanks to @SMAW for reporting)
* Fix Firebase-only "link expired" issue (#529)
* Remove "Install .apk" feature in Google Play variant due to policy change (#531)
* Add donate button (no ticket)

Additional translations:
* Korean (thanks to @YJSofta0f97461d82447ac)
* Portuguese (thanks to @victormagalhaess)
