Update Telethon

The upstream dev doesn't want to make new releases anymore before 2.0,
so this is temporarily using a fork. The main change is API layer 133,
which updates all user/chat IDs to be 64-bit.

requirements.txt

@@ -6,5 +6,7 @@ commonmark>=0.8,<0.10
 aiohttp>=3,<4
 yarl>=1,<2
 mautrix>=0.10.5,<0.11
-telethon>=1.22,<1.24
+#telethon>=1.22,<1.24
+# Temporary patch for 64-bit IDs until upstream telethon 2.0 is ready
+tulir-telethon==1.24.0a1
 telethon-session-sqlalchemy>=0.2.14,<0.3