keep a changelog (awslabs#76)

* keep a changelog

Author: softprops

CHANGELOG.md

@@ -0,0 +1,13 @@
+# 0.2.0
+
+- **New**: We created lambda_runtime_core crate that implements the runtime's main loop and supports handlers that accept and return Vec<u8>. ([#53](https://github.com/awslabs/aws-lambda-rust-runtime/issues/53))
+- **New**: The primary lambda_runtime crate is a wrapper on top of the lambda_runtime_core handler ([#53](https://github.com/awslabs/aws-lambda-rust-runtime/issues/53))
+- **New**: The lambda_http crate, which enables support for API Gateway or ALB requests, treating them as Request structs from the http crate ([#18 by @softprops](https://github.com/awslabs/aws-lambda-rust-runtime/issues/18)).
+- **New**: The lambda_runtime_errors crate introduces the LambdaErrorExt trait that enables the ability to specify custom errorType values for the Lambda Runtime API. The change also includes a companion derive crate that makes it easy to automatically generate LambdaErrorExt implementations for crate-local error types ([#63](https://github.com/awslabs/aws-lambda-rust-runtime/issues/63)).
+- **Fix**: Handlers can now return any error type ([#54](https://github.com/awslabs/aws-lambda-rust-runtime/issues/54))
+- **Fix**: Support for closures as handlers ([#19 by @srijs](https://github.com/awslabs/aws-lambda-rust-runtime/issues/19)).
+- **Fix**: Multiple bug fixes and performance improvements (thanks @Sh4rK).
+
+# 0.1.0
+
+- Initial Release