ESModules compliant export of DayPickerInput

[natepappenhagen]

ESModules compliant export of DayPickerInput
This lib @ 7.4.10 currently blocks me and my team from moving forward with Vite/Rollup because DayPickerInput does not export in an ES Modules compliant way. This should now export DayPickerInput from the index of DayPicker.

this should resolve this open issue:
#1194

So we can import like this:

import { DayPickerInput } from 'react-day-picker';