Add our mainnet and kovan nodes as backups for Portal requests

packages/website/ts/utils/configs.ts

@@ -118,8 +118,8 @@ export const configs = {
     ] as OutdatedWrappedEtherByNetworkId[],
     // The order matters. We first try first node and only then fall back to others.
     PUBLIC_NODE_URLS_BY_NETWORK_ID: {
-        [1]: [`https://mainnet.infura.io/${INFURA_API_KEY}`],
-        [42]: [`https://kovan.infura.io/${INFURA_API_KEY}`],
+        [1]: [`https://mainnet.infura.io/${INFURA_API_KEY}`, 'https://mainnet.0xproject.com'],
+        [42]: [`https://kovan.infura.io/${INFURA_API_KEY}`, 'https://kovan.0xproject.com'],
     } as PublicNodeUrlsByNetworkId,
     SHOULD_DEPRECATE_OLD_WETH_TOKEN: true,
     SYMBOLS_OF_MINTABLE_TOKENS: ['MKR', 'MLN', 'GNT', 'DGD', 'REP'],