feat: fraxtal mainnet/testnet rpc support (#517)

Author: pegahcarter

src/StdChains.sol

@@ -235,6 +235,8 @@ abstract contract StdChains {
         setChainWithDefaultRpcUrl("moonbase", ChainData("Moonbase", 1287, "https://rpc.testnet.moonbeam.network"));
         setChainWithDefaultRpcUrl("base_goerli", ChainData("Base Goerli", 84531, "https://goerli.base.org"));
         setChainWithDefaultRpcUrl("base", ChainData("Base", 8453, "https://mainnet.base.org"));
+        setChainWithDefaultRpcUrl("fraxtal", ChainData("Fraxtal", 252, "https://rpc.frax.com"));
+        setChainWithDefaultRpcUrl("fraxtal_testnet", ChainData("Fraxtal Testnet", 2522, "https://rpc.testnet.frax.com"));
     }
 
     // set chain info, with priority to chainAlias' rpc url in foundry.toml

test/StdChains.t.sol

@@ -70,6 +70,8 @@ contract StdChainsTest is Test {
     //     testRpc("moonbase");
     //     testRpc("base_goerli");
     //     testRpc("base");
+    //     testRpc("fraxtal");
+    //     testRpc("fraxtal_testnet");
     // }
 
     function test_ChainNoDefault() public {