Add RentCast API (#380)

Add RentCast API to Finance

README.md

@@ -751,6 +751,7 @@
 | [Portfolio Optimizer](https://portfoliooptimizer.io/) | Portfolio analysis and optimization | No | Yes | Yes |
 | [Razorpay IFSC](https://razorpay.com/docs/) | Indian Financial Systems Code (Bank Branch Codes) | No | Yes | Unknown |
 | [Real Time Finance](https://github.com/Real-time-finance/finance-websocket-API/) | Websocket API to access realtime stock data | `apiKey` | No | Unknown |
+| [RentCast](https://developers.rentcast.io) | Retrieve real-time property and rental data for real estate in the United States | `apiKey` | Yes | Yes |
 | [Repetiti](https://developers.repetiti.com/) | Repetiti 3d Printer Management Service | `apiKey` | Yes | Yes |
 | [SEC EDGAR Data](https://www.sec.gov/search-filings/edgar-application-programming-interfaces) | API to access annual reports of public US companies | No | Yes | Yes |
 | [SmartAPI](https://smartapi.angelbroking.com/) | Gain access to set of <SmartAPI> and create end-to-end broking services | `apiKey` | Yes | Unknown |