chore: update config_schema

build_helpers/schema.json

@@ -13,6 +13,10 @@
       "description": "The timeframe to use (e.g `1m`, `5m`, `15m`, `30m`, `1h` ...). \nUsually specified in the strategy and missing in the configuration.",
       "type": "string"
     },
+    "proxy_coin": {
+      "description": "Proxy coin - must be used for specific futures modes (e.g. BNFCR)",
+      "type": "string"
+    },
     "stake_currency": {
       "description": "Currency used for staking.",
       "type": "string"