send converted stickers in webp format

bots/modules/stickers.py

@@ -38,8 +38,8 @@ class StickersBotModuleConfig(TelegramBotModuleConfig):
         else:
             target_height = 512
         im = im.resize((target_width, target_height), Image.ANTIALIAS)
-        with tempfile.NamedTemporaryFile(suffix='.png') as f:
-            im.save(f, 'png')
+        with tempfile.NamedTemporaryFile(suffix='.webp') as f:
+            im.save(f, 'webp')
             f.seek(0)
             update.message.reply_document(f, caption=f'{width}x{height} -> {target_width}x{target_height}')