Consider e2e_room_keys.is_verified column as boolean

This column was considered as an int, crashing the whole
migration process

Signed-off-by: Eric <eric@pedr0.net>

changelog.d/4680.bugfix

@@ -0,0 +1,3 @@
+Fix an issue in the database migration script where the 
+`e2e_room_keys.is_verified` column wasn't considered as 
+a boolean

scripts/synapse_port_db

@@ -53,6 +53,7 @@ BOOLEAN_COLUMNS = {
     "group_summary_users": ["is_public"],
     "group_roles": ["is_public"],
     "local_group_membership": ["is_publicised", "is_admin"],
+    "e2e_room_keys": ["is_verified"],
 }