Set the min schema version to 72.

Author: clokep

synapse/storage/schema/__init__.py

@@ -74,13 +74,14 @@
 
 Changes in SCHEMA_VERSION = 72:
     - event_edges.(room_id, is_state) are no longer written to.
+    - Tables related to groups are dropped.
 """
 
 
 SCHEMA_COMPAT_VERSION = (
     # We no longer maintain `event_edges.room_id`, so synapses with SCHEMA_VERSION < 71
     # will break.
-    71
+    72
 )
 """Limit on how far the synapse codebase can be rolled back without breaking db compat