Update Slack MCP server link in GitHub-to-Slack example (#348)

Author: Haniehz1

examples/usecases/mcp_github_to_slack_agent/README.md

@@ -22,7 +22,7 @@ This application creates an MCP Agent that monitors GitHub pull requests and sub
 - Python 3.10 or higher
 - MCP Agent framework
 - [GitHub MCP Server](https://github.com/github/github-mcp-server))
-- [Slack MCP Server](https://github.com/modelcontextprotocol/servers/tree/main/src/slack)
+- [Slack MCP Server](https://github.com/korotovsky/slack-mcp-server/tree/master)
 - Node.js and npm (this is for the Slack server)
 - [Docker](https://www.docker.com/)
 - Access to a GitHub repository

examples/usecases/mcp_github_to_slack_agent/mcp_agent.config.yaml

@@ -24,5 +24,11 @@ mcp:
       description: "Access GitHub API operations"
     slack:
       command: "npx"
-      args: ["-y", "@modelcontextprotocol/server-slack"]
-      description: "Access Slack API operations"
+      args: ["-y",
+        "slack-mcp-server@latest",
+        "--transport",
+        "stdio"]
+      env:
+        SLACK_MCP_XOXP_TOKEN: "ADD_YOUR_TOKEN_HERE"
+        SLACK_MCP_ADD_MESSAGE_TOOL: "true"
+      description: "Access Slack API operations"]