Fix path in use case ex3_1_SubseasonalECVHindcast.md to resolve 'No data files found' error

In the Weekly ECV Subseasonal Hindcast Verification use case, the data is retrieved by running the following code:

library(startR)

ecmwf_path <- paste0('/esarchive/exp/ecmwf/s2s-monthly_ensforhc/',
                     'weekly_mean/$var$_f24h/$sdate$/$var$_$syear$.nc')
forecast.year <- 2016
# Mondays
sdates.seq.mon <- format(seq(as.Date(paste(forecast.year, 01, 04, sep = '-')),
                             as.Date(paste(forecast.year, 12, 31, sep='-')), 
                             by = 'weeks'), format = '%Y%m%d')
# Thursdays (Monday+3days)
sdates.seq.thu <- format(seq(as.Date(paste(forecast.year, 01, 04, sep = '-')) + 3,
                         as.Date(paste(forecast.year, 12, 31, sep = '-')),
                         by = 'weeks'), format = '%Y%m%d')
# Joint dates in order
sdates.seq <- c(sdates.seq.mon, sdates.seq.thu)
ind <- order(as.Date(sdates.seq, format = '%Y%m%d'))  # dates in order
sdates.seq <- sdates.seq[ind]

# Leap years, remove 29th of February:
pos.bis <- which(sdates.seq == paste0(forecast.year,"0229")) 
if(length(pos.bis) != 0) sdates.seq <- sdates.seq[-pos.bis] 

exp <- Start(dat = ecmwf_path, 
              var = 'tas',
              sdate = sdates.seq,
              syear = 'all',     # before hdate
              time = 'all',
              ensemble = "all",
              latitude = indices(1:121),
              longitude = indices(1:240),
              syear_depends = 'sdate',
              return_vars = list(latitude = NULL,
                                 longitude = NULL,
                                 time = c('sdate', 'syear')),
              num_procs = 16, 
              retrieve = FALSE)

Which gives this error:

Error in Start(dat = ecmwf_path, var = "tas", sdate = sdates.seq, syear = "all",  : 
  No data files found for any of the specified datasets.

This is because the directory tas_f24h does not exist in the defined path /esarchive/exp/ecmwf/s2s-monthly_ensforhc/weekly_mean/$var$_f24h/$sdate$/$var$_$syear$.nc. The only directory that exists for the tas variable is tas_f6h, so a solution would be to change the initial path to:

ecmwf_path <- paste0('/esarchive/exp/ecmwf/s2s-monthly_ensforhc/',
                     'weekly_mean/$var$_f6h/$sdate$/$var$_$syear$.nc')

With this change, Start() was able to successfully discover the data dimensions, as expected.

(I am using R/4.1.2 in RStudio Server connected to a WS)

Thanks,

Ariadna