nimbus.prater: use a new set of MEV boost URLs

The one from `flashbots.net` seems to have connectivity issues:
```
REST request was interrupted
```

Signed-off-by: Jakub Sokołowski <jakub@status.im>

ansible/group_vars/nimbus.prater.yml

@@ -73,7 +73,13 @@ beacon_node_suggested_fee_recipient: '{{lookup("bitwarden", "nimbus/wallet/testn
 beacon_node_service_user_pass: '{{lookup("bitwarden", "nimbus/windows", field="password")}}'
 # MEV Payload Builder
 beacon_node_payload_builder_enabled: '{{ node.get("payload_builder", false) }}'
-beacon_node_payload_builder_url: 'https://builder-relay-goerli.flashbots.net/'
+beacon_node_payload_builder_url: '{{ prater_mev_boost_urls[idx] }}'
+prater_mev_boost_urls:
+  - 'https://bloxroute.max-profit.builder.goerli.blxrbdn.com'
+  - 'https://builder-relay-goerli.blocknative.com'
+  - 'https://goerli-relay.securerpc.com'
+  - 'https://goerli.aestus.live'
+  - 'https://relay-stag.ultrasound.money'
 # Light client data
 beacon_node_light_client_data_enabled: '{{ (node.public_api is defined and node.public_api) }}'
 beacon_node_light_client_data_serve: true