fix(run_ss3sim): Removes trailing comma in foreach code

Thanks to @chamberlindw and @peterkuriyama for letting me know and suggesting a fix.

Close #399

R/run_ss3sim.r

@@ -166,7 +166,7 @@ run_ss3sim <- function(iterations,
       message("Running scenarios in parallel.")
       ignore <- foreach::foreach(
         x = arg_list, .packages = "ss3sim",
-        .verbose = FALSE,
+        .verbose = FALSE
       ) %dopar%
         do.call("ss3sim_base", c(x, list(iterations = iterations, ...)))
     }