picom: disable shadow in thunderbird

Author: dikiaap

.picom/picom.conf

@@ -7,7 +7,8 @@ shadow-offset-y = -5;
 shadow-exclude = [
     "class_g = 'firefox' && argb",
     "class_g = 'i3-frame'",
-    "class_g = 'TelegramDesktop' && argb"
+    "class_g = 'TelegramDesktop' && argb",
+    "class_g = 'thunderbird' && argb"
 ];
 
 # Fading