Add Covalent API to Cryptocurrency

README.md

@@ -229,6 +229,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Coinpaprika](https://api.coinpaprika.com) | Cryptocurrencies prices, volume and more | No | Yes | Yes |
 | [CoinRanking](https://docs.coinranking.com/) | Live Cryptocurrency data | No | Yes | Unknown |
 | [CoinStats](https://documenter.getpostman.com/view/5734027/RzZ6Hzr3?version=latest) | Crypto Tracker | No | Yes | Unknown |
+| [Covalent](https://www.covalenthq.com/docs/api/) | Multi-blockchain data aggregator | `apiKey` | Yes | Unknown |
 | [CryptoCompare](https://www.cryptocompare.com/api#) | Cryptocurrencies Comparison | No | Yes | Unknown |
 | [CryptoMarket](https://developers.cryptomkt.com) | Cryptocurrencies Trading platform | `apiKey` | Yes | Yes |
 | [Cryptonator](https://www.cryptonator.com/api/) | Cryptocurrencies Exchange Rates | No | Yes | Unknown |