Fix sticker body

.gitignore

 *.png
 *.ttf
 .env
+session.txt

adacher_matrix.py

@@ -54,9 +54,10 @@ async def echo(room, event):
                     "mimetype": "image/png",
                     "h": height,
                     "w": width,
+                    "size": 0,
                     "thumbnail_url": uri,
                     },
-                "body": json.JSONEncoder().encode(cmd),
+                "body": cmd,
                 "m.relates_to": {
                     "m.in_reply_to": {
                         "event_id": event.event_id