Fixes Malloc (espressif#9012)

Fixes `malloc()` call preventing it from using function pointer reference instead of actually calling the function itself.

libraries/WebServer/src/WebServer.cpp

@@ -135,7 +135,7 @@ bool WebServer::authenticate(const char * username, const char * password){
       authReq = authReq.substring(6);
       authReq.trim();
       char toencodeLen = strlen(username)+strlen(password)+1;
-      char *toencode = (char *)malloc[toencodeLen + 1];
+      char *toencode = (char *)malloc(toencodeLen + 1);
       if(toencode == NULL){
         authReq = "";
         return false;