replace as.character with format for R4.3

[klin333]

in R4.3 the following could give warning:

rhandsontable::rhandsontable(data.frame(x = Sys.Date()))
# Warning message:
# In as.character.POSIXt(as.POSIXlt(x), ...) :
#   as.character(td, ..) no longer obeys a 'format' argument; use format(td, ..) ?

This pull request fixes it

[petersmp]

I am also running into this issue. It looks like this PR would fix the issue.

[J-flem]

Thank you for this branch @klin333. Hopefully it can be pulled into the main branch soon

[jjjpellinen]

Ran into this issue a year ago #427.

This will fix it. And somehow it seems surprisingly time consuming to merge these 2 lines.

[shradha-singh]

Can someone help review and approve this? I am also running into this issue with an R version upgrade.

[ropersam]

Also running into this issue after upgrade within my organisation. Praying for approval 🙏

[adrianbeer]

Same here, seems like this repo isn't being maintained anymore unfortunately...