Use geth instead of parity for goerli

Parity does not work after the merge.

Author: karlb

docker-compose.yml

@@ -76,7 +76,7 @@ services:
       context: ./backend
     restart: always
     environment:
-      - EXPLORER_ETH_RPC=http://parity.goerli.ethnodes.brainbot.com:8545
+      - EXPLORER_ETH_RPC=http://geth.goerli.ethnodes.brainbot.com:8545
     labels:
       - "traefik.enable=true"
       - "traefik.frontend.rule=Host:goerli.explorer.raiden.network; Path: /json"