Log Message:
py-httpcore: updated to 0.13.3

0.13.3 (May 6th, 2021)

Added

- Support HTTP/2 prior knowledge, using `httpcore.SyncConnectionPool(http1=False)`.

Fixed

- Handle cases where environment does not provide `select.poll` support.

0.13.2 (April 29th, 2021)

Added

- Improve error message for specific case of `RemoteProtocolError` where server \ 
disconnects without sending a response.

0.13.1 (April 28th, 2021)

Fixed

- More resiliant testing for closed connections.
- Don't raise exceptions on ungraceful connection closes.

0.13.0 (April 21st, 2021)

The 0.13 release updates the core API in order to match the HTTPX Transport API,
introduced in HTTPX 0.18 onwards.

An example of making requests with the new interface is:

```python
with httpcore.SyncConnectionPool() as http:
    status_code, headers, stream, extensions = http.handle_request(
        method=b'GET',
        url=(b'https', b'example.org', 443, b'/'),
        headers=[(b'host', b'example.org'), (b'user-agent', b'httpcore')]
        stream=httpcore.ByteStream(b''),
        extensions={}
    )
    body = stream.read()
    print(status_code, body)
```

Changed

- The `.request()` method is now `handle_request()`.
- The `.arequest()` method is now `.handle_async_request()`.
- The `headers` argument is no longer optional.
- The `stream` argument is no longer optional.
- The `ext` argument is now named `extensions`, and is no longer optional.
- The `"reason"` extension keyword is now named \ 
`"reason_phrase"`.
- The `"reason_phrase"` and `"http_version"` extensions now \ 
use byte strings for their values.
- The `httpcore.PlainByteStream()` class becomes `httpcore.ByteStream()`.

Added

- Streams now support a `.read()` interface.

Fixed

- Task cancelation no longer leaks connections from the connection pool.