Mangum

* Remove WebSocket support and misc cleanup/removals by jordaneremieff in https://github.com/jordaneremieff/mangum/pull/234
* Replace awslambdaric-stubs with new types, refactor import style. by jordaneremieff in https://github.com/jordaneremieff/mangum/pull/235
* Improve logging by aminalaee in https://github.com/jordaneremieff/mangum/pull/230

* HTTP Gateway V2: Remove use of obsolete multiValueHeaders by IlyaSukhanov in https://github.com/jordaneremieff/mangum/pull/216
* mypy - Argument "api_gateway_base_path" to "Mangum" has incompatible type "str"; expected "Dict[str, Any]" by relsunkaev in https://github.com/jordaneremieff/mangum/pull/220
* Added explicit python3.9 and 3.10 support by relsunkaev in https://github.com/jordaneremieff/mangum/pull/224
* Fix aws_api_gateway handler not accepting combined headers and multiValueHeaders by Feriixu in https://github.com/jordaneremieff/mangum/pull/229

* Fix unhandled `api_gateway_base_path` in `AwsHttpGateway`. [200](https://github.com/jordaneremieff/mangum/pull/204). Thanks [xpayn](https://github.com/xpayn)!

* Exclude `tests/` directory from package. [200](https://github.com/jordaneremieff/mangum/pull/200). Thanks [bradsbrown](https://github.com/bradsbrown)!

* Make `boto3` optional [197](https://github.com/jordaneremieff/mangum/pull/197).

* Reintroduce WebSocket support [190](https://github.com/jordaneremieff/mangum/pull/190). Thanks [eduardovra](https://github.com/eduardovra)!

* Resolve several issues with ALB/ELB support [184](https://github.com/jordaneremieff/mangum/pull/184), [#189](https://github.com/jordaneremieff/mangum/pull/189), [#186](https://github.com/jordaneremieff/mangum/pull/186), [#182](https://github.com/jordaneremieff/mangum/pull/182). Thanks [nathanglover](https://github.com/nathanglover) & [jurasofish](https://github.com/jurasofish)!

* Refactor handlers to be separate from core logic [170](https://github.com/jordaneremieff/mangum/pull/170). Thanks [four43](https://github.com/four43)!