Add API documentation for CNB

Co-authored-by: Pavel Busko <pavel.busko@sap.com>
Co-authored-by: Ralf Pannemans <ralf.pannemans@sap.com>

docs/v3/source/includes/concepts/_lifecycles.md.erb

@@ -7,7 +7,7 @@ pull a Docker image from a registry to run an app.
 
 Name | Type | Description
 ---- | ---- | -----------
-**type** | _string_ | Type of the lifecycle; valid values are `buildpack`, `docker`
+**type** | _string_ | Type of the lifecycle; valid values are `buildpack`, `cnb`, `docker`
 **data** | _object_ | Data that is used during staging and running for a lifecycle
 
 ### Buildpack lifecycle
@@ -42,6 +42,34 @@ Name | Type | Description
 **data.buildpacks** | _list of strings_ | A list of the names of buildpacks, URLs from which they may be downloaded, or `null` to auto-detect a suitable buildpack during staging
 **data.stack** | _string_ | The root filesystem to use with the buildpack, for example `cflinuxfs4`
 
+### Cloud Native Buildpacks Lifecycle
+
+```
+Example Cloud Native Buildpacks lifecycle
+```
+
+```json
+{
+  "type": "cnb",
+  "data": {
+    "buildpacks": ["docker://example.org/java-buildpack:latest"],
+    "stack": "cflinuxfs4"
+  }
+}
+```
+
+This lifecycle allows Cloud Foundry to stage an application using the [Cloud Native Buildpacks](https://buildpacks.io/).
+
+**Note**: the **data.buildpacks** field is required (at least 1 buildpack must be set).
+
+#### Cloud Native Buildpacks lifecycle object
+
+Name | Type | Description
+---- | ---- | -----------
+**type** | _string_ | `cnb`
+**data.buildpacks** | _list of strings_ | A list of URLs with either `docker://` or `http(s)://` scheme, pointing to the Cloud Native Buildpack OCI image. <br/>When the scheme is `http(s)://`, an OCI tarball is expected to be present at the specified location.
+**data.stack** | _string_ | The root filesystem to use with the buildpack, for example `cflinuxfs4`
+
 ### Docker lifecycle
 
 ```

docs/v3/source/includes/resources/apps/_list.md.erb

@@ -39,7 +39,7 @@ Name | Type | Description
 **per_page** | _integer_ | Number of results per page; valid values are 1 through 5000
 **order_by** | _string_ | Value to sort by. Defaults to ascending; prepend with `-` to sort descending. Valid values are `created_at`, `updated_at`, `name`, `state`
 **label_selector** | _string_ | A query string containing a list of [label selector](#labels-and-selectors) requirements
-**lifecycle_type** | _string_ | [Lifecycle](#lifecycles) type to filter by; valid values are `buildpack`, `docker`
+**lifecycle_type** | _string_ | [Lifecycle](#lifecycles) type to filter by; valid values are `buildpack`, `cnb`, `docker`
 **include**| _list of strings_ | Optionally include a list of unique related resources in the response; valid values are `space` and `space.organization`
 **created_ats** | _[timestamp](#timestamps)_ | Timestamp to filter by. When filtering on equality, several comma-delimited timestamps may be passed. Also supports filtering with [relational operators](#relational-operators)
 **updated_ats** | _[timestamp](#timestamps)_ | Timestamp to filter by. When filtering on equality, several comma-delimited timestamps may be passed. Also supports filtering with [relational operators](#relational-operators)

docs/v3/source/includes/resources/manifests/_object.md.erb

@@ -89,7 +89,8 @@ This configuration is specified per application and applies to all of the applic
 Name | Type | Description
 ----- | ---- | -----------
 **name** | _string_ | Name of the app
-**buildpacks** | _list of strings_ | a) An empty array, which will automatically select the appropriate default buildpack according to the coding language <br>b) An array of one or more URLs pointing to buildpacks <br>c) An array of one or more installed buildpack names <br>Replaces the legacy `buildpack` field
+**lifecycle** | _string_ | Type of the lifecycle; valid values are `buildpack`, `cnb`, `docker`.
+**buildpacks** | _list of strings_ | a) An empty array, which will automatically select the appropriate default buildpack according to the coding language (incompatible with **lifecycle: cnb**) <br>b) An array of one or more URLs pointing to buildpacks <br>c) An array of one or more installed buildpack names <br>Replaces the legacy `buildpack` field
 **docker** | _object_ | If present, the created app will have Docker lifecycle type; the value of this key is ignored by the API but may be used by clients to source the registry address of the image and credentials, if needed; the [generate manifest endpoint](#generate-a-manifest-for-an-app) will return the registry address of the image and username provided with this key
 **env** | _object_ | A key-value mapping of environment variables to be used for the app when running
 **no-route** | _boolean_ | When set to `true`, any routes specified with the `routes` attribute will be ignored and any existing routes will be removed