Wrong link in frontend/README.md

[alvarogalloc]

https://github.com/GraphiteEditor/Graphite/blob/master/frontend/README.md has a hyperlink 'Tauri' that refers to https://tauri.studio/ instead of https://tauri.app/ in line 5

[Keavon]

Thanks for noticing! This is small enough it's not worth tracking so I'll just close this issue but we'll fix it in that PR above.