Add PR 2073 to changelog
### SDK Features
+* `private/model/api`: SDK APIs input/output are not consistently generated ([#2073](https://github.com/aws/aws-sdk-go/pull/2073))
+ * Updates the SDK's API code generation to generate the API input and output types consistently. This ensures that the SDK will no longer rename input/output types unexpectedly as in [#2070](https://github.com/aws/aws-sdk-go/issues/2070). SDK API input and output parameter types will always be the API name with a suffix of Input and Output.
+ * Existing service APIs which were incorrectly modeled have been preserved to ensure they do not break.
+ * Fixes [#2070](https://github.com/aws/aws-sdk-go/issues/2070)
### SDK Enhancements
* `service/s3/s3manager`: Document default behavior for Upload's MaxNumParts ([#2077](https://github.com/aws/aws-sdk-go/issues/2077))
* Fixes [#2015](https://github.com/aws/aws-sdk-go/issues/2015)
### SDK Bugs
+* `private/model/api`: SDK APIs input/output are not consistently generated ([#2073](https://github.com/aws/aws-sdk-go/pull/2073))
+ * Fixes EFS service breaking change in v1.14.26 where `FileSystemDescription` was incorrectly renamed to `UpdateFileSystemOutput.
+ * Fixes [#2070](https://github.com/aws/aws-sdk-go/issues/2070)
