SS3 update to .ss_new naming convention

[CassidyPeterson-NOAA]

SS3 v3.30.19.01 renames new data file as data_echo.ss_new (instead of previously named data.ss_new). This triggers an error in the function SSMSE:::copy_model_files(). See lines of code below.

if (!all(c("control.ss_new", "data.ss_new", "starter.ss_new", 
            "forecast.ss_new", "ss.par") %in% list.files(OM_in_dir))) {
            stop(".ss_new files not found in the original OM directory ", 
                OM_in_dir, ". Please run the model to make the .ss_new files available.")
        }