Alpaca-trade-api

In this release we add asyncio support for the historic endpoints
* Bars
* Quotes
* Trades

We also support the latest endpoints:
* latest quote
* latest trade

We also add
* LULDs to stream.

In this release we:
* Add daily bars to data stream (f826e5bfd00419db5fcad45dae15afb6fdf917d9)
* Add support for closing partial position (253bd6d7aa4854235bcc5773ca7116f85e67e62e)
* Fix a data v2 websocket reconnection issue (b649fb4066a423877c1cf378a63edf752d8f9ebe)
* extend `list_order()` to be able to filter by symbol list (e203f38840d5e396154bf30aafb6adf8888e3551)
* update the websockets package and the websocket-client package (d5b5e26326cfc6397ef28aa022abfecbe9b57a10, 59b4fb86a0272eb666f5bb7323c9f2a5b9faee21)
* fix example code - `overnight_hold.py` (797d508a339536694f29c3717598af21c77c207b)

In this release we
- added the v2 latest trades / quotes endpoints
- added the v2 snapshot / snapshots endpoints

In this release, we add support for fractional amounts (`qty`) and notional values (`notional`) in [POST/v2/orders](https://alpaca.markets/docs/api-documentation/api-v2/orders/) requests, via `submit_order()`:
- `qty` is now an optional `float` kwarg
- `notional` has been added as an optional `float` kwarg
- `side` is now a kwarg (default is `"buy"`)
- `type` is now a kwarg (default is `"market"`)
- `time_in_force` is now a kwarg (default is `"day"`)

With these changes, we encourage users to call `submit_order()` with named arguments instead of positional ones.

For examples, please refer to the [docs](https://github.com/alpacahq/alpaca-trade-api-python#using-submit_order).

* Added ability to stop the ws connection (d214cbf50d39f85426c74fb6a3721a5195b3493c)
* updated the websocket examples for v2 (a77bc6b099e63b7deb71ad037869790246126e29)
* removed old, unsupported example code
* only support `'raw'` adjustment for `get_bars()` for now (aa748d717c40505966a396dfca75db2ca565658b)

In this release we upgrade our service to Alpaca Data V2 as described [here](https://alpaca.markets/docs/api-documentation/api-v2/market-data/alpaca-data-api-v2/). (1391436dbba635efb56615739d91fdbb2f23cd9c)
We dropped support for the Polygon stream data and Rest APIs.<br>
To learn how to use the new functionality:
* refer to the [docs](https://alpaca.markets/docs/api-documentation/api-v2/market-data/alpaca-data-api-v2/)
* check out the readme file examples
* check out the [sample code](https://github.com/alpacahq/alpaca-trade-api-python/tree/master/examples)