chore: set UPSTREAM_VERSION to kona-node/v1.6.2

Author: tropibot[bot]

docker-compose.yml

@@ -4,7 +4,7 @@ services:
     build:
       context: op-node
       args:
-        UPSTREAM_VERSION: op-proposer/v1.10.2
+        UPSTREAM_VERSION: kona-node/v1.6.2
     environment:
       - CUSTOM_L1_RPC
       - CUSTOM_L1_BEACON_API