Add readthedocs build dependencies [skip ci]

Fix Doesn't support pydantic v2.0 (just released today) #99

Allow Dict as option value, fix #88

Fix javascript fails to set the hidden value when the remove icon is …

…clicked #86

Fix Widget is initialised with wrong date string for European locals #85

Fix build error due to missing sphinx

Release 4.0.0

Add Bootstrap 5 support

bootstrap_datepicker_plus v2.0.0 with tests, coverage and badges