CHANGELOG.md: new --header-file flag for 'add api' and 'generate k8s' (#1257)

Author: estroz

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### Added
 
+- New optional flag `--header-file` for commands [`operator-sdk generate k8s`](https://github.com/operator-framework/operator-sdk/blob/master/doc/sdk-cli-reference.md#k8s) and [`operator-sdk add api`](https://github.com/operator-framework/operator-sdk/blob/master/doc/sdk-cli-reference.md#api) to supply a boilerplate header file for generated code. ([#1239](https://github.com/operator-framework/operator-sdk/pull/1239))
+
 ### Changed
 
 - Updated the helm-operator to store release state in kubernetes secrets in the same namespace of the custom resource that defines the release. ([#1102](https://github.com/operator-framework/operator-sdk/pull/1102))

doc/sdk-cli-reference.md

@@ -123,6 +123,10 @@ Currently only runs `deepcopy-gen` to generate the required `DeepCopy()` functio
 
 **Note**: This command must be run every time the api (spec and status) for a custom resource type is updated.
 
+### Flags
+
+* `--header-file` string - Path to file containing headers for generated files (optional).
+
 #### Example
 
 ```console
@@ -306,6 +310,7 @@ Adds the API definition for a new custom resource under `pkg/apis` and generates
 
 * `--api-version` string - CRD APIVersion in the format `$GROUP_NAME/$VERSION` (e.g app.example.com/v1alpha1)
 * `--kind` string - CRD Kind. (e.g AppService)
+* `--header-file` string - Path to file containing headers for generated files (optional).
 
 #### Example