Use SVG icon instead of PNG.

--- kitty-0.7.1/setup.py
+++ kitty-0.7.1/setup.py
@@ -507,9 +507,9 @@
     safe_makedirs(launcher_dir)
     build_linux_launcher(args, launcher_dir, for_bundle, sh_launcher)
     if not is_macos:  # {{{ linux desktop gunk
-        icdir = os.path.join(ddir, 'share', 'icons', 'hicolor', '256x256', 'apps')
+        icdir = os.path.join(ddir, 'share', 'icons', 'hicolor', 'scalable', 'apps')
         safe_makedirs(icdir)
-        shutil.copy2('logo/kitty.png', icdir)
+        shutil.copy2('logo/kitty.svg', icdir)
         deskdir = os.path.join(ddir, 'share', 'applications')
         safe_makedirs(deskdir)
         with open(os.path.join(deskdir, 'kitty.desktop'), 'w') as f: