Add docstring for api_gateway_base_path, release notes

Author: jordaneremieff

docs/release-notes.md

@@ -1,3 +1,11 @@
+## 0.12.0
+
+* 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)!
+
 ## 0.11.0
 
 * Remove deprecated `enable_lifespan` parameter [#109](https://github.com/jordaneremieff/mangum/issues/109).

mangum/adapter.py

@@ -39,6 +39,8 @@ class Mangum:
     specification. This will usually be an ASGI framework application instance.
     * **lifespan** - A string to configure lifespan support. Choices are `auto`, `on`,
     and `off`. Default is `auto`.
+    * **api_gateway_base_path** - Base path to strip from URL when using a custom
+    domain name.
     * **text_mime_types** - A list of MIME types to include with the defaults that
     should not return a binary response in API Gateway.
     * **dsn** - A connection string required to configure a supported WebSocket backend.