Update the Server URL for Alpha Vantage MCP

We are now hosting the official Alpha Vantage MCP server at https://mcp.alphavantage.co/, hence this PR to update the target URL. 

Submitted by Steve (Cofounder of Alpha Vantage)

Author: SteveAlphaVantage

README.md

@@ -74,7 +74,7 @@ Official integrations are maintained by companies building production ready MCP
 - <img height="12" width="12" src="https://www.alipayplus.com/favicon.ico" alt="AlipayPlus Logo" /> **[AlipayPlus](https://github.com/alipay/global-alipayplus-mcp)** - Connect your AI Agents to AlipayPlus Checkout Payment.
 - <img height="12" width="12" src="https://cdn.allvoicelab.com/resources/workbench/dist/icon-dark.ico" alt="AllVoiceLab Logo" /> **[AllVoiceLab](https://www.allvoicelab.com/mcp)** - An AI voice toolkit with TTS, voice cloning, and video translation, now available as an MCP server for smarter agent integration.
 - <img height="12" width="12" src="https://files.alpaca.markets/webassets/favicon-32x32.png" alt="Alpaca Logo" /> **[Alpaca](https://github.com/alpacahq/alpaca-mcp-server)** – Alpaca's MCP server lets you trade stocks and options, analyze market data, and build strategies through [Alpaca's Trading API](https://alpaca.markets/)
-- <img height="12" width="12" src="https://www.alphavantage.co/logo.png/" alt="AlphaVantage Logo" /> **[AlphaVantage](https://github.com/calvernaz/alphavantage)** - Connect to 100+ APIs for financial market data, including stock prices, fundamentals, and more from [AlphaVantage](https://www.alphavantage.co)
+- <img height="12" width="12" src="https://www.alphavantage.co/logo.png/" alt="AlphaVantage Logo" /> **[AlphaVantage](https://mcp.alphavantage.co/)** - Connect to 100+ APIs for financial market data, including stock prices, fundamentals, and more from [AlphaVantage](https://www.alphavantage.co)
 - <img height="12" width="12" src="https://www.antom.com/favicon.ico" alt="Antom Logo" /> **[Antom](https://github.com/alipay/global-antom-mcp)** - Connect your AI Agents to Antom Checkout Payment.
 - <img height="12" width="12" src="https://developers.anytype.io/img/favicon.ico" alt="Anytype Logo" /> **[Anytype](https://github.com/anyproto/anytype-mcp)** - An MCP server enabling AI assistants to interact with [Anytype](https://anytype.io) - a local and collaborative wiki - to organize objects, lists, and more through natural language.
 - <img height="12" width="12" src="https://doris.apache.org/images/favicon.ico" alt="Apache Doris Logo" /> **[Apache Doris](https://github.com/apache/doris-mcp-server)** - MCP Server For [Apache Doris](https://doris.apache.org/), an MPP-based real-time data warehouse.