fix: ensure 2+ items in each override in schema (#1628)

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

bin/generate_schema.py

@@ -200,6 +200,7 @@ description: An overrides array
 items:
   type: object
   required: ["select"]
+  minProperties: 2
   additionalProperties: false
   properties:
     select: {}