Log Message:
py-test-httpx: updated to 0.23.1

0.23.1
Fixed
- Version `0.23.0` introduced a regression removing the support for mutating \ 
json content provided in `httpx_mock.add_response`.
 - This is fixed, you can now expect the JSON return being as it was when \ 
provided to `httpx_mock.add_response`:
```python
   mutating_json = {"content": "request 1"}
   # This will return {"content": "request 1"}
   httpx_mock.add_response(json=mutating_json)

   mutating_json["content"] = "request 2"
   # This will return {"content": "request 2"}
   httpx_mock.add_response(json=mutating_json)
```

0.23.0
Removed
- Python `3.7` and `3.8` are no longer supported.

Fixed
- `httpx_mock.add_response` is now returning a new `httpx.Response` instance \ 
upon each matching request. Preventing unnecessary recursion in streams.