The file is actually named Shantae_Half-Genie_Hero_Update_v1.05.nsp.rar (someone added .rar by mistake, or it's a multi-part RAR).
If you are looking for new gameplay content, these were introduced in different updates or editions: shantae halfgenie hero nspupdate 105rar
The best way to ensure you have version 1.0.5 (or the latest equivalent) is through official platforms: The file is actually named Shantae_Half-Genie_Hero_Update_v1