fread autostart is now an error

hi @bogind !
Using the new version of data.table on github, `fread(autostart=)` is now an error (after 6 years of warning).
This results in a new check error for easycsv:
```
* checking examples ... ERROR
Running examples in 'easycsv-Ex.R' failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: fread_zip
> ### Title: read multiple csv files into named data frames
> ### Aliases: fread_zip
> ### Keywords: ~utilities ~misc
>
> ### ** Examples
>
>
> require(easycsv)
> filezip <- system.file("exampleZips", "example_tables.zip", package="easycsv")
> fread_zip(filezip)
Error in data.table::fread(input = tbl, sep = sep, nrows = nrows, header = header, :
'autostart' is deprecated. Consider skip='string' or skip=n. This argument will be removed in the next release.
Calls: fread_zip -> -> stopf -> raise_condition -> signal
Execution halted
```
Can you please run `data.table::update_dev_pkg()` to get the new version of `data.table` for testing, then change easycsv so that it checks without error, then submit a new version of easycsv to CRAN? (so that it will be compatible with the new version of `data.table` that we plan to submit to CRAN in the next few weeks)
thanks!