[1.21.5] 1.4.5 for Fabric

Dropped 1.21.3 Fabric.
Added support for 1.21.5 for Fabric and NeoForge.
Fixed a bug where some skins would sometimes not load.
Changed interpolation to be less smooth, to be more accurate to the Legacy Console Editions. (Can be reverted to the old smooth animation in Legacy Skins's config screen.)
Skin packs downloaded by Legacy Skins are now automatically added to Legacy4J's Global Resource Packs.
Ported to use Legacy4J 1.8.1
Replaced the "Replace this text before release!" text with a download progress text, showing the download progress for each resource pack.
Removed the "changed parent screen" text logged into the console every time the auth screen is closed.