[entropy] add arbitrum goerli (#1139)

fortuna/config.yaml

@@ -9,3 +9,6 @@ chains:
     geth_rpc_addr: https://api.testnet.evm.eosnetwork.com/
     contract_addr: 0xD42c7a708E74AD19401D907a14146F006c851Ee3
     legacy_tx: true
+  arbitrum-goerli:
+    geth_rpc_addr: https://arbitrum-goerli.publicnode.com
+    contract_addr: 0xd9eAcfFB8e80b7193042499485EF8369b08E85B6

target_chains/ethereum/entropy_sdk/solidity/README.md

@@ -24,6 +24,7 @@ The following table lists the current deployments of entropy.
 | avalanche-fuji  | 0xD42c7a708E74AD19401D907a14146F006c851Ee3 | 0x6CC14824Ea2918f5De5C2f75A9Da968ad4BD6344 |
 | optimism-goerli | 0x28F16Af4D87523910b843a801454AEde5F9B0459 | 0x6CC14824Ea2918f5De5C2f75A9Da968ad4BD6344 |
 | eos-evm-testnet | 0xD42c7a708E74AD19401D907a14146F006c851Ee3 | 0x6CC14824Ea2918f5De5C2f75A9Da968ad4BD6344 |
+| arbitrum-goerli | 0xd9eAcfFB8e80b7193042499485EF8369b08E85B6 | 0x6CC14824Ea2918f5De5C2f75A9Da968ad4BD6344 |
 ```
 
 Choose one of these networks and instantiate an `IEntropy` contract in your solidity contract: