Covid

Breaking Changes

PR: 72

1. Uses worldometers as default
2. Deprecates John Hopkins source
3. Uses Pydantic V2
4. OBJECTID type change from str to int

Feature

* Moves to python 3.8
* Fixes pydantic version for <2.0.0

Feature
- adds new fields for worldometers (new_cases, new_deaths, active_cases)
- old fields should still work (confirmed, active)

Bugfix
- updates dependencies to latest versions

bugfix allow None values

Bugfix
- fixes John Hopkins API `recovered` attribute None values