Add missing property boolean followRedirects

Add missing boolean property `followRedirects ` to ServerOptions interface

types/http-proxy/index.d.ts

@@ -207,6 +207,8 @@ declare namespace Server {
     headers?: {[header: string]: string};
     /** Timeout (in milliseconds) when proxy receives no response from target. Default: 120000 (2 minutes) */
     proxyTimeout?: number;
+    /** Specify whether you want to follow redirects. Default: false */
+    followRedirects?: boolean;
     /** If set to true, none of the webOutgoing passes are called and it's your responsibility to appropriately return the response by listening and acting on the proxyRes event */
     selfHandleResponse?: boolean;
   }