Fix `dropdownAutoWidth` so it actually works
Fix `dropdownAutoWidth` so it actually works

Previously the `dropdownAutoWidth` option didn't work because the
dropdown was being absolutely positioned, so setting the width to
`auto` didn't actually have an effect. This cannot be solved by
just setting the width on the container, because that is also
absolutely positioned.

This closes https://github.com/select2/select2/issues/3101

fk/select2,select2/select2,murb/select2,NabiKAZ/select2,bottomline/select2,select2/select2,murb/select2,ZaArsProgger/select2,NabiKAZ/select2,iestruch/select2,megahallon/select2,megahallon/select2,michael-brade/select2,bottomline/select2,michael-brade/select2,ZaArsProgger/select2,fk/select2,inway/select2,iestruch/select2,inway/select2