✨ Add support for Pydantic v1 and above 🎉 (#646)

* Make compatible with pydantic v1

* Remove unused import

* Remove unused ignores

* Update pydantic version

* Fix minor formatting issue

* ⏪ Revert removing iterate_in_threadpool

* ✨ Add backwards compatibility with Pydantic 0.32.2

with deprecation warnings

* ✅ Update tests to not break when using Pydantic < 1.0.0

* 📝 Update docs for Pydantic version 1.0.0

* 📌 Update Pydantic range version to support from 0.32.2

* 🎨 Format test imports

* ✨ Add support for Pydantic < 1.2 for populate_validators

* ✨ Add backwards compatibility for Pydantic < 1.2.0 with required fields

* 📌 Relax requirement for Pydantic to < 2.0.0 🎉 🚀

* 💚 Update pragma coverage for older Pydantic versions

docs/src/response_model/tutorial004.py

@@ -21,6 +21,6 @@ items = {
 }
 
 
-@app.get("/items/{item_id}", response_model=Item, response_model_skip_defaults=True)
+@app.get("/items/{item_id}", response_model=Item, response_model_exclude_unset=True)
 async def read_item(item_id: str):
     return items[item_id]