add support for Emerald (from Oasis)

ethers-core/src/types/chain.rs

@@ -39,6 +39,8 @@ pub enum Chain {
     ArbitrumTestnet = 421611,
     Cronos = 25,
     CronosTestnet = 338,
+    Emerald = 42262,
+    EmeraldTestnet = 42261,
 }
 
 impl fmt::Display for Chain {
@@ -69,6 +71,8 @@ impl fmt::Display for Chain {
             Chain::ArbitrumTestnet => "arbitrum-testnet",
             Chain::Cronos => "cronos",
             Chain::CronosTestnet => "cronos-testnet",
+            Chain::Emerald => "emerald",
+            Chain::EmeraldTestnet => "emerald-testnet",
         };
 
         write!(formatter, "{}", chain)
@@ -123,6 +127,8 @@ impl TryFrom<u64> for Chain {
             421611 => Chain::ArbitrumTestnet,
             25 => Chain::Cronos,
             338 => Chain::CronosTestnet,
+            42262 => Chain::Emerald,
+            42261 => Chain::EmeraldTestnet,
             _ => return Err(ParseChainError(chain.to_string())),
         })
     }

ethers-etherscan/src/lib.rs

@@ -100,6 +100,7 @@ impl Client {
             Chain::Moonbeam | Chain::MoonbeamDev | Chain::Moonriver => {
                 std::env::var("MOONSCAN_API_KEY")?
             }
+            Chain::Emerald | Chain::EmeraldTestnet => std::env::var("OASIS_API_KEY")?,
             Chain::Dev => return Err(EtherscanError::LocalNetworksNotSupported),
         };
         Self::new(chain, api_key)
@@ -263,6 +264,13 @@ impl ClientBuilder {
             Chain::Moonriver => {
                 urls("https://api-moonriver.moonscan.io/api", "https://moonriver.moonscan.io")
             }
+            Chain::Emerald => {
+                urls("https://explorer.emerald.oasis.dev/api", "https://explorer.emerald.oasis.dev")
+            }
+            Chain::EmeraldTestnet => urls(
+                "https://testnet.explorer.emerald.oasis.dev/api",
+                "https://testnet.explorer.emerald.oasis.dev",
+            ),
             Chain::Dev => return Err(EtherscanError::LocalNetworksNotSupported),
             chain => return Err(EtherscanError::ChainNotSupported(chain)),
         };