⬆️ Update Pydantic to 0.21.0 (#90)

* ⬆️ Upgrade Pydantic and others (isort), update docs after changes by isort

* 🎨 Format with newest isort, update type hints in jsonable_encoder

* 🔧 Update test script, to avoid Pydantic type errors

* ⬆️ Update pyproject.toml with latest Pydantic

docs/tutorial/application-configuration.md

@@ -27,7 +27,7 @@ But you can configure it with the parameter `openapi_url`.
 
 For example, to set it to be served at `/api/v1/openapi.json`:
 
-```Python hl_lines="4"
+```Python hl_lines="3"
 {!./src/application_configuration/tutorial002.py!}
 ```
 
@@ -46,6 +46,6 @@ You can configure the two documentation user interfaces included:
 
 For example, to set Swagger UI to be served at `/documentation` and disable ReDoc:
 
-```Python hl_lines="4 5"
+```Python hl_lines="3"
 {!./src/application_configuration/tutorial003.py!}
 ```